81716564 has 24 divisors (see below), whose sum is σ = 144648000. Its totient is φ = 40392000.

The previous prime is 81716477. The next prime is 81716581. The reversal of 81716564 is 46561718.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 199592 + ... + 200000.

It is an arithmetic number, because the mean of its divisors is an integer number (6027000).

Almost surely, 2^81716564 is an apocalyptic number.

It is an amenable number.

81716564 is a deficient number, since it is larger than the sum of its proper divisors (62931436).

81716564 is a wasteful number, since it uses less digits than its factorization.

81716564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 863 (or 861 counting only the distinct ones).

The product of its digits is 40320, while the sum is 38.

The square root of 81716564 is about 9039.7214558857. The cubic root of 81716564 is about 433.9470087565.

The spelling of 81716564 in words is "eighty-one million, seven hundred sixteen thousand, five hundred sixty-four".