81964920 has 32 divisors (see below), whose sum is σ = 245895120. Its totient is φ = 21857280.

The previous prime is 81964901. The next prime is 81964931. The reversal of 81964920 is 2946918.

It is a super-2 number, since 2×81964920² = 13436496221212800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 341401 + ... + 341640.

Almost surely, 2^81964920 is an apocalyptic number.

It is an amenable number.

81964920 is an abundant number, since it is smaller than the sum of its proper divisors (163930200).

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

81964920 is a wasteful number, since it uses less digits than its factorization.

81964920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683055 (or 683051 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 81964920 is about 9053.4479619645. The cubic root of 81964920 is about 434.3861867278.

The spelling of 81964920 in words is "eighty-one million, nine hundred sixty-four thousand, nine hundred twenty".