81974256 has 160 divisors (see below), whose sum is σ = 266649600. Its totient is φ = 21563136.

The previous prime is 81974209. The next prime is 81974279. The reversal of 81974256 is 65247918.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 213841 + ... + 214223.

It is an arithmetic number, because the mean of its divisors is an integer number (1666560).

Almost surely, 2^81974256 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 81974256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133324800).

81974256 is an abundant number, since it is smaller than the sum of its proper divisors (184675344).

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

81974256 is a wasteful number, since it uses less digits than its factorization.

81974256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428 (or 408 counting only the distinct ones).

The product of its digits is 120960, while the sum is 42.

The square root of 81974256 is about 9053.9635519478. The cubic root of 81974256 is about 434.4026786427.

The spelling of 81974256 in words is "eighty-one million, nine hundred seventy-four thousand, two hundred fifty-six".