81965904 has 40 divisors (see below), whose sum is σ = 212775072. Its totient is φ = 27189120.

The previous prime is 81965899. The next prime is 81965941. The reversal of 81965904 is 40956918.

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, 6082 + ... + 14174.

Almost surely, 2^81965904 is an apocalyptic number.

It is an amenable number.

81965904 is an abundant number, since it is smaller than the sum of its proper divisors (130809168).

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

81965904 is a wasteful number, since it uses less digits than its factorization.

81965904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8315 (or 8309 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 81965904 is about 9053.5023057378. The cubic root of 81965904 is about 434.3879250092.

The spelling of 81965904 in words is "eighty-one million, nine hundred sixty-five thousand, nine hundred four".