81579974 has 32 divisors (see below), whose sum is σ = 149299200. Its totient is φ = 32635008.

The previous prime is 81579973. The next prime is 81579983. The reversal of 81579974 is 47997518.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81579973) 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, 28877 + ... + 31575.

It is an arithmetic number, because the mean of its divisors is an integer number (4665600).

Almost surely, 2^81579974 is an apocalyptic number.

81579974 is a deficient number, since it is larger than the sum of its proper divisors (67719226).

81579974 is a wasteful number, since it uses less digits than its factorization.

81579974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2852.

The product of its digits is 635040, while the sum is 50.

The square root of 81579974 is about 9032.1633067610. The cubic root of 81579974 is about 433.7050917581.

The spelling of 81579974 in words is "eighty-one million, five hundred seventy-nine thousand, nine hundred seventy-four".