81144172 has 12 divisors (see below), whose sum is σ = 143948056. Its totient is φ = 40016160.

The previous prime is 81144163. The next prime is 81144191. The reversal of 81144172 is 27144118.

It is a self number, because there is not a number n which added to its sum of digits gives 81144172.

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 3 ways as a sum of consecutive naturals, for example, 138654 + ... + 139237.

Almost surely, 2^81144172 is an apocalyptic number.

It is an amenable number.

81144172 is a deficient number, since it is larger than the sum of its proper divisors (62803884).

81144172 is a wasteful number, since it uses less digits than its factorization.

81144172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277968 (or 277966 counting only the distinct ones).

The product of its digits is 1792, while the sum is 28.

The square root of 81144172 is about 9008.0059946694. The cubic root of 81144172 is about 432.9314251178.

The spelling of 81144172 in words is "eighty-one million, one hundred forty-four thousand, one hundred seventy-two".