81696625 has 32 divisors (see below), whose sum is σ = 109025280. Its totient is φ = 60984000.

The previous prime is 81696623. The next prime is 81696631. The reversal of 81696625 is 52669618.

It is not a de Polignac number, because 81696625 - 2¹ = 81696623 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81696623) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 112012 + ... + 112738.

It is an arithmetic number, because the mean of its divisors is an integer number (3407040).

Almost surely, 2^81696625 is an apocalyptic number.

It is an amenable number.

81696625 is a deficient number, since it is larger than the sum of its proper divisors (27328655).

81696625 is a wasteful number, since it uses less digits than its factorization.

81696625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 802 (or 792 counting only the distinct ones).

The product of its digits is 155520, while the sum is 43.

The square root of 81696625 is about 9038.6185338247. The cubic root of 81696625 is about 433.9117112484.

The spelling of 81696625 in words is "eighty-one million, six hundred ninety-six thousand, six hundred twenty-five".