1918720872 has 40 divisors (see below), whose sum is σ = 5374196850. Its totient is φ = 639573408.

The previous prime is 1918720847. The next prime is 1918720883. The reversal of 1918720872 is 2780278191.

It can be written as a sum of positive squares in only one way, i.e., 1892772036 + 25948836 = 43506^2 + 5094^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1479847 + ... + 1481142.

Almost surely, 2^1918720872 is an apocalyptic number.

1918720872 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1918720872 is an abundant number, since it is smaller than the sum of its proper divisors (3455475978).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1918720872 is a wasteful number, since it uses less digits than its factorization.

1918720872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2961007 (or 2960994 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 45.

The square root of 1918720872 is about 43803.2061840226. The cubic root of 1918720872 is about 1242.6169307802.

The spelling of 1918720872 in words is "one billion, nine hundred eighteen million, seven hundred twenty thousand, eight hundred seventy-two".