81697944 has 16 divisors (see below), whose sum is σ = 204244920. Its totient is φ = 27232640.

The previous prime is 81697939. The next prime is 81697969. The reversal of 81697944 is 44979618.

It is a junction number, because it is equal to n+sod(n) for n = 81697893 and 81697902.

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, 1702017 + ... + 1702064.

Almost surely, 2^81697944 is an apocalyptic number.

It is an amenable number.

81697944 is an abundant number, since it is smaller than the sum of its proper divisors (122546976).

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

81697944 is a wasteful number, since it uses less digits than its factorization.

81697944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3404090 (or 3404086 counting only the distinct ones).

The product of its digits is 435456, while the sum is 48.

The square root of 81697944 is about 9038.6914982203. The cubic root of 81697944 is about 433.9140464182.

The spelling of 81697944 in words is "eighty-one million, six hundred ninety-seven thousand, nine hundred forty-four".