81304128 has 56 divisors (see below), whose sum is σ = 239024160. Its totient is φ = 27100800.

The previous prime is 81304123. The next prime is 81304129. The reversal of 81304128 is 82140318.

It is a super-2 number, since 2×81304128² = 13220722459680768, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81304123) 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, 21798 + ... + 25253.

Almost surely, 2^81304128 is an apocalyptic number.

It is an amenable number.

81304128 is an abundant number, since it is smaller than the sum of its proper divisors (157720032).

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

81304128 is a wasteful number, since it uses less digits than its factorization.

81304128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47072 (or 47056 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 81304128 is about 9016.8801699923. The cubic root of 81304128 is about 433.2157114029.

The spelling of 81304128 in words is "eighty-one million, three hundred four thousand, one hundred twenty-eight".