81375156 has 18 divisors (see below), whose sum is σ = 205698402. Its totient is φ = 27125040.

The previous prime is 81375097. The next prime is 81375167. The reversal of 81375156 is 65157318.

81375156 is a `hidden beast` number, since 8 + 137 + 515 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 46376100 + 34999056 = 6810^2 + 5916^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 2260421 = 81375156 / (8 + 1 + 3 + 7 + 5 + 1 + 5 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 81375156.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1130175 + ... + 1130246.

It is an arithmetic number, because the mean of its divisors is an integer number (11427689).

Almost surely, 2^81375156 is an apocalyptic number.

It is an amenable number.

81375156 is an abundant number, since it is smaller than the sum of its proper divisors (124323246).

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

81375156 is a wasteful number, since it uses less digits than its factorization.

81375156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2260431 (or 2260426 counting only the distinct ones).

The product of its digits is 25200, while the sum is 36.

The square root of 81375156 is about 9020.8179230045. The cubic root of 81375156 is about 433.3418283673.

The spelling of 81375156 in words is "eighty-one million, three hundred seventy-five thousand, one hundred fifty-six".