81974224 has 20 divisors (see below), whose sum is σ = 159988644. Its totient is φ = 40686848.

The previous prime is 81974209. The next prime is 81974279. The reversal of 81974224 is 42247918.

It can be written as a sum of positive squares in 2 ways, for example, as 35188624 + 46785600 = 5932^2 + 6840^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16507 + ... + 20890.

Almost surely, 2^81974224 is an apocalyptic number.

It is an amenable number.

81974224 is a deficient number, since it is larger than the sum of its proper divisors (78014420).

81974224 is a wasteful number, since it uses less digits than its factorization.

81974224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37542 (or 37536 counting only the distinct ones).

The product of its digits is 32256, while the sum is 37.

The square root of 81974224 is about 9053.9617847658. The cubic root of 81974224 is about 434.4026221173.

It can be divided in two parts, 8197 and 4224, that added together give a palindrome (12421).

The spelling of 81974224 in words is "eighty-one million, nine hundred seventy-four thousand, two hundred twenty-four".