81572680 has 32 divisors (see below), whose sum is σ = 209759040. Its totient is φ = 27967680.

The previous prime is 81572669. The next prime is 81572713. The reversal of 81572680 is 8627518.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 145386 + ... + 145945.

It is an arithmetic number, because the mean of its divisors is an integer number (6554970).

Almost surely, 2^81572680 is an apocalyptic number.

It is an amenable number.

81572680 is an abundant number, since it is smaller than the sum of its proper divisors (128186360).

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

81572680 is a wasteful number, since it uses less digits than its factorization.

81572680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291349 (or 291345 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 81572680 is about 9031.7595184992. The cubic root of 81572680 is about 433.6921656315.

The spelling of 81572680 in words is "eighty-one million, five hundred seventy-two thousand, six hundred eighty".