72991431 has 12 divisors (see below), whose sum is σ = 105604408. Its totient is φ = 48581424.

The previous prime is 72991427. The next prime is 72991447. The reversal of 72991431 is 13419927.

It is not a de Polignac number, because 72991431 - 2² = 72991427 is a prime.

It is a super-2 number, since 2×72991431² = 10655497998855522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72991031) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 520 + ... + 12093.

Almost surely, 2^72991431 is an apocalyptic number.

72991431 is a deficient number, since it is larger than the sum of its proper divisors (32612977).

72991431 is a wasteful number, since it uses less digits than its factorization.

72991431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13262 (or 13259 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The square root of 72991431 is about 8543.5022678056. The cubic root of 72991431 is about 417.9175661409.

The spelling of 72991431 in words is "seventy-two million, nine hundred ninety-one thousand, four hundred thirty-one".