81939576 has 32 divisors (see below), whose sum is σ = 205742160. Its totient is φ = 27194112.

The previous prime is 81939569. The next prime is 81939601. The reversal of 81939576 is 67593918.

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, 1735 + ... + 12918.

Almost surely, 2^81939576 is an apocalyptic number.

It is an amenable number.

81939576 is an abundant number, since it is smaller than the sum of its proper divisors (123802584).

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

81939576 is a wasteful number, since it uses less digits than its factorization.

81939576 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14895 (or 14891 counting only the distinct ones).

The product of its digits is 408240, while the sum is 48.

The square root of 81939576 is about 9052.0481660230. The cubic root of 81939576 is about 434.3414105869.

The spelling of 81939576 in words is "eighty-one million, nine hundred thirty-nine thousand, five hundred seventy-six".