81908912 has 10 divisors (see below), whose sum is σ = 158698548. Its totient is φ = 40954448.

The previous prime is 81908899. The next prime is 81908917. The reversal of 81908912 is 21980918.

It is not an unprimeable number, because it can be changed into a prime (81908917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2559638 + ... + 2559669.

Almost surely, 2^81908912 is an apocalyptic number.

It is an amenable number.

81908912 is a deficient number, since it is larger than the sum of its proper divisors (76789636).

81908912 is a wasteful number, since it uses less digits than its factorization.

81908912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5119315 (or 5119309 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 81908912 is about 9050.3542472104. The cubic root of 81908912 is about 434.2872230689.

The spelling of 81908912 in words is "eighty-one million, nine hundred eight thousand, nine hundred twelve".