81820917524 has 12 divisors (see below), whose sum is σ = 143228656704. Its totient is φ = 40898444184.

The previous prime is 81820917517. The next prime is 81820917557. The reversal of 81820917524 is 42571902818.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2988314 + ... + 3015569.

It is an arithmetic number, because the mean of its divisors is an integer number (11935721392).

Almost surely, 2^81820917524 is an apocalyptic number.

It is an amenable number.

81820917524 is a deficient number, since it is larger than the sum of its proper divisors (61407739180).

81820917524 is a wasteful number, since it uses less digits than its factorization.

81820917524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6007294 (or 6007292 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 47.

The spelling of 81820917524 in words is "eighty-one billion, eight hundred twenty million, nine hundred seventeen thousand, five hundred twenty-four".