81696624 has 20 divisors (see below), whose sum is σ = 211049736. Its totient is φ = 27232192.

The previous prime is 81696623. The next prime is 81696631. The reversal of 81696624 is 42669618.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 850959 + ... + 851054.

Almost surely, 2^81696624 is an apocalyptic number.

It is an amenable number.

81696624 is an abundant number, since it is smaller than the sum of its proper divisors (129353112).

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

81696624 is a wasteful number, since it uses less digits than its factorization.

81696624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1702024 (or 1702018 counting only the distinct ones).

The product of its digits is 124416, while the sum is 42.

The square root of 81696624 is about 9038.6184785065. The cubic root of 81696624 is about 433.9117094780.

It can be divided in two parts, 816966 and 24, that multiplied together give a square (19607184 = 4428²).

The spelling of 81696624 in words is "eighty-one million, six hundred ninety-six thousand, six hundred twenty-four".