81974916 has 45 divisors (see below), whose sum is σ = 214725511. Its totient is φ = 27270648.

The previous prime is 81974897. The next prime is 81974917. The reversal of 81974916 is 61947918.

It is a happy number.

The square root of 81974916 is 9054.

It is a perfect power (a square), and thus also a powerful number.

81974916 is nontrivially palindromic in base 5.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81974917) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 162721 + ... + 163223.

Almost surely, 2^81974916 is an apocalyptic number.

81974916 is the 9054-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81974916

81974916 is an abundant number, since it is smaller than the sum of its proper divisors (132750595).

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

81974916 is an equidigital number, since it uses as much as digits as its factorization.

81974916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1022 (or 508 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The cubic root of 81974916 is about 434.4038444762.

The spelling of 81974916 in words is "eighty-one million, nine hundred seventy-four thousand, nine hundred sixteen".