81568880 has 40 divisors (see below), whose sum is σ = 196192800. Its totient is φ = 31501568.

The previous prime is 81568871. The next prime is 81568897. The reversal of 81568880 is 8886518.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15260 + ... + 19899.

It is an arithmetic number, because the mean of its divisors is an integer number (4904820).

Almost surely, 2^81568880 is an apocalyptic number.

81568880 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81568880 is an abundant number, since it is smaller than the sum of its proper divisors (114623920).

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

81568880 is a wasteful number, since it uses less digits than its factorization.

81568880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35201 (or 35195 counting only the distinct ones).

The product of its (nonzero) digits is 122880, while the sum is 44.

The square root of 81568880 is about 9031.5491472947. The cubic root of 81568880 is about 433.6854311226.

The spelling of 81568880 in words is "eighty-one million, five hundred sixty-eight thousand, eight hundred eighty".