81577472 has 40 divisors (see below), whose sum is σ = 164326536. Its totient is φ = 40456192.

The previous prime is 81577459. The next prime is 81577487. The reversal of 81577472 is 27477518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69563 + ... + 70725.

Almost surely, 2^81577472 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81577472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82163268).

81577472 is an abundant number, since it is smaller than the sum of its proper divisors (82749064).

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

81577472 is a wasteful number, since it uses less digits than its factorization.

81577472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1318 (or 1302 counting only the distinct ones).

The product of its digits is 109760, while the sum is 41.

The square root of 81577472 is about 9032.0248006745. The cubic root of 81577472 is about 433.7006579035.

It can be divided in two parts, 815 and 77472, that added together give a palindrome (78287).

The spelling of 81577472 in words is "eighty-one million, five hundred seventy-seven thousand, four hundred seventy-two".