72864531 has 24 divisors (see below), whose sum is σ = 107883360. Its totient is φ = 47376000.

The previous prime is 72864527. The next prime is 72864553. The reversal of 72864531 is 13546827.

72864531 is a `hidden beast` number, since 7 + 2 + 8 + 645 + 3 + 1 = 666.

It is not a de Polignac number, because 72864531 - 2² = 72864527 is a prime.

It is a super-2 number, since 2×72864531² = 10618479755699922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (72864511) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 63975 + ... + 65103.

It is an arithmetic number, because the mean of its divisors is an integer number (4495140).

Almost surely, 2^72864531 is an apocalyptic number.

72864531 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

72864531 is a deficient number, since it is larger than the sum of its proper divisors (35018829).

72864531 is a wasteful number, since it uses less digits than its factorization.

72864531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1307 (or 1304 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 72864531 is about 8536.0723403683. The cubic root of 72864531 is about 417.6752340285.

The spelling of 72864531 in words is "seventy-two million, eight hundred sixty-four thousand, five hundred thirty-one".