81974736 has 30 divisors (see below), whose sum is σ = 229415810. Its totient is φ = 27324864.

The previous prime is 81974723. The next prime is 81974741. The reversal of 81974736 is 63747918.

It can be written as a sum of positive squares in only one way, i.e., 41525136 + 40449600 = 6444^2 + 6360^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81974691 and 81974700.

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 5 ways as a sum of consecutive naturals, for example, 284491 + ... + 284778.

Almost surely, 2^81974736 is an apocalyptic number.

It is an amenable number.

81974736 is an abundant number, since it is smaller than the sum of its proper divisors (147441074).

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

81974736 is a wasteful number, since it uses less digits than its factorization.

81974736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 569283 (or 569274 counting only the distinct ones).

The product of its digits is 254016, while the sum is 45.

The square root of 81974736 is about 9053.9900596367. The cubic root of 81974736 is about 434.4035265222.

The spelling of 81974736 in words is "eighty-one million, nine hundred seventy-four thousand, seven hundred thirty-six".