Number

1,980

1,980 is a composite number, even, a calendar year.

Abundant Number Harshad / Niven Pronic / Oblong Year

Properties

Parity: Even
Digit count: 4
Digit sum: 18
Digital root: 9
Palindrome: No
Divisor count: 36
σ(n) — sum of divisors: 6,552

Primality

Prime factorization: 2 ² × 3 ² × 5 × 11

Divisors & multiples

All divisors (36)

1 · 2 · 3 · 4 · 5 · 6 · 9 · 10 · 11 · 12 · 15 · 18 · 20 · 22 · 30 · 33 · 36 · 44 · 45 · 55 · 60 · 66 · 90 · 99 · 110 · 132 · 165 · 180 · 198 · 220 · 330 · 396 · 495 · 660 · 990 · 1980

Aliquot sum (sum of proper divisors): 4,572

Factor pairs (a × b = 1,980)

1 × 1980

2 × 990

3 × 660

4 × 495

5 × 396

6 × 330

9 × 220

10 × 198

11 × 180

12 × 165

15 × 132

18 × 110

20 × 99

22 × 90

30 × 66

33 × 60

36 × 55

44 × 45

First multiples

1,980 · 3,960 · 5,940 · 7,920 · 9,900 · 11,880 · 13,860 · 15,840 · 17,820 · 19,800

Representations

In words: one thousand nine hundred eighty
Ordinal: 1980th
Roman numeral: MCMLXXX
Binary: 11110111100
Octal: 3674
Hexadecimal: 7BC

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1980, here are decompositions:

7 + 1973 = 1980
29 + 1951 = 1980
31 + 1949 = 1980
47 + 1933 = 1980
67 + 1913 = 1980
73 + 1907 = 1980
79 + 1901 = 1980
101 + 1879 = 1980

Showing the first eight; more decompositions exist.

Hex color

#0007BC

RGB(0, 7, 188)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.188.