81179664 has 20 divisors (see below), whose sum is σ = 209714256. Its totient is φ = 27059872.

The previous prime is 81179639. The next prime is 81179701. The reversal of 81179664 is 46697118.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 845574 + ... + 845669.

Almost surely, 2^81179664 is an apocalyptic number.

It is an amenable number.

81179664 is an abundant number, since it is smaller than the sum of its proper divisors (128534592).

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

81179664 is a wasteful number, since it uses less digits than its factorization.

81179664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1691254 (or 1691248 counting only the distinct ones).

The product of its digits is 72576, while the sum is 42.

The square root of 81179664 is about 9009.9758046290. The cubic root of 81179664 is about 432.9945364994.

The spelling of 81179664 in words is "eighty-one million, one hundred seventy-nine thousand, six hundred sixty-four".