81375280 has 60 divisors (see below), whose sum is σ = 220097520. Its totient is φ = 27898752.

The previous prime is 81375269. The next prime is 81375289. The reversal of 81375280 is 8257318.

It is not an unprimeable number, because it can be changed into a prime (81375289) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 6460 + ... + 14299.

It is an arithmetic number, because the mean of its divisors is an integer number (3668292).

Almost surely, 2^81375280 is an apocalyptic number.

81375280 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81375280 is an abundant number, since it is smaller than the sum of its proper divisors (138722240).

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

81375280 is a wasteful number, since it uses less digits than its factorization.

81375280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20786 (or 20773 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 81375280 is about 9020.8247959929. The cubic root of 81375280 is about 433.3420484769.

The spelling of 81375280 in words is "eighty-one million, three hundred seventy-five thousand, two hundred eighty".