81716624 has 30 divisors (see below), whose sum is σ = 174031830. Its totient is φ = 37143040.

The previous prime is 81716611. The next prime is 81716629. The reversal of 81716624 is 42661718.

It can be written as a sum of positive squares in only one way, i.e., 77440000 + 4276624 = 8800^2 + 2068^2 .

It is not an unprimeable number, because it can be changed into a prime (81716629) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19169 + ... + 23040.

It is an arithmetic number, because the mean of its divisors is an integer number (5801061).

Almost surely, 2^81716624 is an apocalyptic number.

It is an amenable number.

81716624 is an abundant number, since it is smaller than the sum of its proper divisors (92315206).

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

81716624 is a wasteful number, since it uses less digits than its factorization.

81716624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42239 (or 42222 counting only the distinct ones).

The product of its digits is 16128, while the sum is 35.

The square root of 81716624 is about 9039.7247745714. The cubic root of 81716624 is about 433.9471149644.

The spelling of 81716624 in words is "eighty-one million, seven hundred sixteen thousand, six hundred twenty-four".