72165978 has 40 divisors (see below), whose sum is σ = 167292180. Its totient is φ = 23224320.

The previous prime is 72165953. The next prime is 72165991. The reversal of 72165978 is 87956127.

It can be written as a sum of positive squares in 2 ways, for example, as 70509609 + 1656369 = 8397^2 + 1287^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2983 + ... + 12378.

Almost surely, 2^72165978 is an apocalyptic number.

72165978 is an abundant number, since it is smaller than the sum of its proper divisors (95126202).

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

72165978 is a wasteful number, since it uses less digits than its factorization.

72165978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15404 (or 15395 counting only the distinct ones).

The product of its digits is 211680, while the sum is 45.

The square root of 72165978 is about 8495.0560916335. The cubic root of 72165978 is about 416.3361934970.

The spelling of 72165978 in words is "seventy-two million, one hundred sixty-five thousand, nine hundred seventy-eight".