81820565364 has 24 divisors (see below), whose sum is σ = 191051156800. Its totient is φ = 27254021184.

The previous prime is 81820565353. The next prime is 81820565413. The reversal of 81820565364 is 46356502818.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2420089 + ... + 2453664.

Almost surely, 2^81820565364 is an apocalyptic number.

It is an amenable number.

81820565364 is an abundant number, since it is smaller than the sum of its proper divisors (109230591436).

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

81820565364 is a wasteful number, since it uses less digits than its factorization.

81820565364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4875159 (or 4875157 counting only the distinct ones).

The product of its (nonzero) digits is 1382400, while the sum is 48.

The spelling of 81820565364 in words is "eighty-one billion, eight hundred twenty million, five hundred sixty-five thousand, three hundred sixty-four".