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Number

21,601

21,601 is a prime, odd.

Arithmetic Number Deficient Number Evil Number Prime Pythagorean Prime Recamán's Sequence Squarefree Twin Prime

Properties

Parity
Odd
Digit count
5
Digit sum
10
Digit product
0
Digital root
1
Palindrome
No
Bit width
15 bits
Reversed
10,612
Recamán's sequence
a(40,637) = 21,601
Square (n²)
466,603,201
Cube (n³)
10,079,095,744,801
Divisor count
2
σ(n) — sum of divisors
21,602
φ(n) — Euler's totient
21,600

Primality

21,601 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 21601
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 21,601)
1 × 21601
First multiples
21,601 · 43,202 (double) · 64,803 · 86,404 · 108,005 · 129,606 · 151,207 · 172,808 · 194,409 · 216,010

Sums & aliquot sequence

As a sum of two squares: 24² + 145²
As consecutive integers: 10,800 + 10,801

Representations

In words
twenty-one thousand six hundred one
Ordinal
21601st
Binary
101010001100001
Octal
52141
Hexadecimal
0x5461
Base64
VGE=
One's complement
43,934 (16-bit)
In other bases
ternary (3) 1002122001
quaternary (4) 11101201
quinary (5) 1142401
senary (6) 244001
septenary (7) 116656
nonary (9) 32561
undecimal (11) 15258
duodecimal (12) 10601
tridecimal (13) 9aa8
tetradecimal (14) 7c2d
pentadecimal (15) 6601

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹𒁹 · 𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓏺
Greek (Milesian)
͵καχαʹ
Mayan (base 20)
𝋢·𝋮·𝋠·𝋡
Chinese
二萬一千六百零一
Chinese (financial)
貳萬壹仟陸佰零壹
In other modern scripts
Eastern Arabic ٢١٦٠١ Devanagari २१६०१ Bengali ২১৬০১ Tamil ௨௧௬௦௧ Thai ๒๑๖๐๑ Tibetan ༢༡༦༠༡ Khmer ២១៦០១ Lao ໒໑໖໐໑ Burmese ၂၁၆၀၁

Digit at this position in famous constants

π — Pi (π)
Digit 21,601 = 3
e — Euler's number (e)
Digit 21,601 = 8
φ — Golden ratio (φ)
Digit 21,601 = 1
√2 — Pythagoras's (√2)
Digit 21,601 = 6
ln 2 — Natural log of 2
Digit 21,601 = 8
γ — Euler-Mascheroni (γ)
Digit 21,601 = 6

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 21,599 (gap of 2)
  • Next prime: 21,611 (gap of 10)

Pair status: twin with 21599.

Unicode codepoint
CJK Unified Ideograph-5461
U+5461
Other letter (Lo)

UTF-8 encoding: E5 91 A1 (3 bytes).

Hex color
#005461
RGB(0, 84, 97)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.84.97.

Address
0.0.84.97
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.84.97

Unspecified address (0.0.0.0/8) — "this network" placeholder.

Position in π

The digit sequence 21601 first appears in π at position 140,861 of the decimal expansion (the 140,861ordinal-suffix:st digit after the integer 3).

Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.