81057372 has 24 divisors (see below), whose sum is σ = 206328192. Its totient is φ = 24562800.

The previous prime is 81057367. The next prime is 81057391. The reversal of 81057372 is 27375018.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 306904 + ... + 307167.

It is an arithmetic number, because the mean of its divisors is an integer number (8597008).

Almost surely, 2^81057372 is an apocalyptic number.

It is an amenable number.

81057372 is an abundant number, since it is smaller than the sum of its proper divisors (125270820).

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

81057372 is a wasteful number, since it uses less digits than its factorization.

81057372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 614089 (or 614087 counting only the distinct ones).

The product of its (nonzero) digits is 11760, while the sum is 33.

The square root of 81057372 is about 9003.1867691390. The cubic root of 81057372 is about 432.7770009862. Note that the first 3 decimals are identical.

The spelling of 81057372 in words is "eighty-one million, fifty-seven thousand, three hundred seventy-two".