81580828 has 24 divisors (see below), whose sum is σ = 168789600. Its totient is φ = 33757248.

The previous prime is 81580823. The next prime is 81580843. The reversal of 81580828 is 82808518.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81580823) 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, 49423 + ... + 51046.

It is an arithmetic number, because the mean of its divisors is an integer number (7032900).

Almost surely, 2^81580828 is an apocalyptic number.

It is an amenable number.

81580828 is an abundant number, since it is smaller than the sum of its proper divisors (87208772).

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

81580828 is a wasteful number, since it uses less digits than its factorization.

81580828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100509 (or 100507 counting only the distinct ones).

The product of its (nonzero) digits is 40960, while the sum is 40.

The square root of 81580828 is about 9032.2105821333. The cubic root of 81580828 is about 433.7066051314.

The spelling of 81580828 in words is "eighty-one million, five hundred eighty thousand, eight hundred twenty-eight".