81304664 has 32 divisors (see below), whose sum is σ = 175219200. Its totient is φ = 34645920.

The previous prime is 81304649. The next prime is 81304669. The reversal of 81304664 is 46640318.

It is a super-2 number, since 2×81304664² = 13220896776305792, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81304664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81304669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5969 + ... + 14079.

It is an arithmetic number, because the mean of its divisors is an integer number (5475600).

Almost surely, 2^81304664 is an apocalyptic number.

It is an amenable number.

81304664 is an abundant number, since it is smaller than the sum of its proper divisors (93914536).

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

81304664 is a wasteful number, since it uses less digits than its factorization.

81304664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8303 (or 8299 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 81304664 is about 9016.9098919752. The cubic root of 81304664 is about 433.2166633969.

The spelling of 81304664 in words is "eighty-one million, three hundred four thousand, six hundred sixty-four".