72991728 has 30 divisors (see below), whose sum is σ = 204275864. Its totient is φ = 24330528.

The previous prime is 72991703. The next prime is 72991733. The reversal of 72991728 is 82719927.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 253300 + ... + 253587.

Almost surely, 2^72991728 is an apocalyptic number.

It is an amenable number.

72991728 is an abundant number, since it is smaller than the sum of its proper divisors (131284136).

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

72991728 is a wasteful number, since it uses less digits than its factorization.

72991728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 506901 (or 506892 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 72991728 is about 8543.5196494185. The cubic root of 72991728 is about 417.9181329716.

The spelling of 72991728 in words is "seventy-two million, nine hundred ninety-one thousand, seven hundred twenty-eight".