81580870 has 32 divisors (see below), whose sum is σ = 176659200. Its totient is φ = 26498016.

The previous prime is 81580867. The next prime is 81580879. The reversal of 81580870 is 7808518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81580879) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29340 + ... + 31999.

It is an arithmetic number, because the mean of its divisors is an integer number (5520600).

Almost surely, 2^81580870 is an apocalyptic number.

81580870 is an abundant number, since it is smaller than the sum of its proper divisors (95078330).

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

81580870 is a wasteful number, since it uses less digits than its factorization.

81580870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61372.

The product of its (nonzero) digits is 17920, while the sum is 37.

The square root of 81580870 is about 9032.2129071452. The cubic root of 81580870 is about 433.7066795593.

The spelling of 81580870 in words is "eighty-one million, five hundred eighty thousand, eight hundred seventy".