81947524 has 12 divisors (see below), whose sum is σ = 143601948. Its totient is φ = 40918400.

The previous prime is 81947507. The next prime is 81947527. The reversal of 81947524 is 42574918.

It can be written as a sum of positive squares in 2 ways, for example, as 40576900 + 41370624 = 6370^2 + 6432^2 .

It is not an unprimeable number, because it can be changed into a prime (81947527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10417 + ... + 16504.

It is an arithmetic number, because the mean of its divisors is an integer number (11966829).

Almost surely, 2^81947524 is an apocalyptic number.

It is an amenable number.

81947524 is a deficient number, since it is larger than the sum of its proper divisors (61654424).

81947524 is a wasteful number, since it uses less digits than its factorization.

81947524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27686 (or 27684 counting only the distinct ones).

The product of its digits is 80640, while the sum is 40.

The square root of 81947524 is about 9052.4871720428. The cubic root of 81947524 is about 434.3554535931.

The spelling of 81947524 in words is "eighty-one million, nine hundred forty-seven thousand, five hundred twenty-four".