81904712 has 16 divisors (see below), whose sum is σ = 153719100. Its totient is φ = 40912960.

The previous prime is 81904709. The next prime is 81904721. The reversal of 81904712 is 21740918.

It can be written as a sum of positive squares in 2 ways, for example, as 78039556 + 3865156 = 8834^2 + 1966^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5114 + ... + 13782.

Almost surely, 2^81904712 is an apocalyptic number.

It is an amenable number.

81904712 is a deficient number, since it is larger than the sum of its proper divisors (71814388).

81904712 is a wasteful number, since it uses less digits than its factorization.

81904712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9856 (or 9852 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 81904712 is about 9050.1222091196. The cubic root of 81904712 is about 434.2798000365.

The spelling of 81904712 in words is "eighty-one million, nine hundred four thousand, seven hundred twelve".