81500928 has 36 divisors (see below), whose sum is σ = 216913368. Its totient is φ = 27166720.

The previous prime is 81500921. The next prime is 81500929. The reversal of 81500928 is 82900518.

It is a happy number.

It is a super-2 number, since 2×81500928² = 13284802529722368, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81500921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52293 + ... + 53828.

Almost surely, 2^81500928 is an apocalyptic number.

It is an amenable number.

81500928 is an abundant number, since it is smaller than the sum of its proper divisors (135412440).

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

81500928 is a wasteful number, since it uses less digits than its factorization.

81500928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106140 (or 106126 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 33.

The square root of 81500928 is about 9027.7864396540. The cubic root of 81500928 is about 433.5649685981.

It can be divided in two parts, 81500 and 928, that added together give a palindrome (82428).

The spelling of 81500928 in words is "eighty-one million, five hundred thousand, nine hundred twenty-eight".