81716816 has 20 divisors (see below), whose sum is σ = 158894592. Its totient is φ = 40711776.

The previous prime is 81716749. The next prime is 81716827. The reversal of 81716816 is 61861718.

It is a self number, because there is not a number n which added to its sum of digits gives 81716816.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4496 + ... + 13551.

Almost surely, 2^81716816 is an apocalyptic number.

It is an amenable number.

81716816 is a deficient number, since it is larger than the sum of its proper divisors (77177776).

81716816 is a wasteful number, since it uses less digits than its factorization.

81716816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18338 (or 18332 counting only the distinct ones).

The product of its digits is 16128, while the sum is 38.

The square root of 81716816 is about 9039.7353943575. The cubic root of 81716816 is about 433.9474548290.

The spelling of 81716816 in words is "eighty-one million, seven hundred sixteen thousand, eight hundred sixteen".