18981796520 has 16 divisors (see below), whose sum is σ = 42709042260. Its totient is φ = 7592718592.

The previous prime is 18981796513. The next prime is 18981796567. The reversal of 18981796520 is 2569718981.

It can be written as a sum of positive squares in 2 ways, for example, as 18485665444 + 496131076 = 135962^2 + 22274^2 .

It is a super-2 number, since 2×18981796520² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 237272417 + ... + 237272496.

Almost surely, 2^18981796520 is an apocalyptic number.

18981796520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18981796520 is an abundant number, since it is smaller than the sum of its proper divisors (23727245740).

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

18981796520 is a wasteful number, since it uses less digits than its factorization.

18981796520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474544924 (or 474544920 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 56.

The spelling of 18981796520 in words is "eighteen billion, nine hundred eighty-one million, seven hundred ninety-six thousand, five hundred twenty".