81564976 has 10 divisors (see below), whose sum is σ = 158032172. Its totient is φ = 40782480.

The previous prime is 81564943. The next prime is 81565007. The reversal of 81564976 is 67946518.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2548890 + ... + 2548921.

Almost surely, 2^81564976 is an apocalyptic number.

It is an amenable number.

81564976 is a deficient number, since it is larger than the sum of its proper divisors (76467196).

81564976 is a wasteful number, since it uses less digits than its factorization.

81564976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5097819 (or 5097813 counting only the distinct ones).

The product of its digits is 362880, while the sum is 46.

The square root of 81564976 is about 9031.3330134593. Note that the first 3 decimals coincide. The cubic root of 81564976 is about 433.6785120830.

The spelling of 81564976 in words is "eighty-one million, five hundred sixty-four thousand, nine hundred seventy-six".