81536144 has 20 divisors (see below), whose sum is σ = 166291440. Its totient is φ = 38622240.

The previous prime is 81536141. The next prime is 81536177. The reversal of 81536144 is 44163518.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 81536144.

It is not an unprimeable number, because it can be changed into a prime (81536141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133802 + ... + 134409.

It is an arithmetic number, because the mean of its divisors is an integer number (8314572).

Almost surely, 2^81536144 is an apocalyptic number.

It is an amenable number.

81536144 is an abundant number, since it is smaller than the sum of its proper divisors (84755296).

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

81536144 is a wasteful number, since it uses less digits than its factorization.

81536144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268238 (or 268232 counting only the distinct ones).

The product of its digits is 11520, while the sum is 32.

The square root of 81536144 is about 9029.7366517524. The cubic root of 81536144 is about 433.6274064366.

The spelling of 81536144 in words is "eighty-one million, five hundred thirty-six thousand, one hundred forty-four".