72661800816 has 80 divisors (see below), whose sum is σ = 227526865920. Its totient is φ = 22018726080.

The previous prime is 72661800787. The next prime is 72661800817. The reversal of 72661800816 is 61800816627.

It is a happy number.

72661800816 is a `hidden beast` number, since 7 + 26 + 618 + 0 + 0 + 8 + 1 + 6 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72661800817) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7640640 + ... + 7650143.

It is an arithmetic number, because the mean of its divisors is an integer number (2844085824).

Almost surely, 2^72661800816 is an apocalyptic number.

It is an amenable number.

72661800816 is an abundant number, since it is smaller than the sum of its proper divisors (154865065104).

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

72661800816 is a wasteful number, since it uses less digits than its factorization.

72661800816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15290811 (or 15290799 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 72661800816 in words is "seventy-two billion, six hundred sixty-one million, eight hundred thousand, eight hundred sixteen".