81943172 has 12 divisors (see below), whose sum is σ = 143495436. Its totient is φ = 40944480.

The previous prime is 81943139. The next prime is 81943187. The reversal of 81943172 is 27134918.

It can be written as a sum of positive squares in 2 ways, for example, as 22714756 + 59228416 = 4766^2 + 7696^2 .

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1022 + ... + 12842.

It is an arithmetic number, because the mean of its divisors is an integer number (11957953).

Almost surely, 2^81943172 is an apocalyptic number.

It is an amenable number.

81943172 is a deficient number, since it is larger than the sum of its proper divisors (61552264).

81943172 is a wasteful number, since it uses less digits than its factorization.

81943172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13558 (or 13556 counting only the distinct ones).

The product of its digits is 12096, while the sum is 35.

The square root of 81943172 is about 9052.2467929238. The cubic root of 81943172 is about 434.3477643293.

The spelling of 81943172 in words is "eighty-one million, nine hundred forty-three thousand, one hundred seventy-two".