81397372 has 12 divisors (see below), whose sum is σ = 162794800. Its totient is φ = 34884576.

The previous prime is 81397333. The next prime is 81397397. The reversal of 81397372 is 27379318.

81397372 is an admirable number.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

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 3 ways as a sum of consecutive naturals, for example, 1453497 + ... + 1453552.

Almost surely, 2^81397372 is an apocalyptic number.

It is an amenable number.

81397372 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81397372 is a wasteful number, since it uses less digits than its factorization.

81397372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2907060 (or 2907058 counting only the distinct ones).

The product of its digits is 63504, while the sum is 40.

The square root of 81397372 is about 9022.0492129006. The cubic root of 81397372 is about 433.3812599194.

The spelling of 81397372 in words is "eighty-one million, three hundred ninety-seven thousand, three hundred seventy-two".