81330857924 has 6 divisors (see below), whose sum is σ = 142329001374. Its totient is φ = 40665428960.

The previous prime is 81330857899. The next prime is 81330857939. The reversal of 81330857924 is 42975803318.

It can be written as a sum of positive squares in only one way, i.e., 56060032900 + 25270825024 = 236770^2 + 158968^2 .

It is a super-2 number, since 2×81330857924² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10166357237 + ... + 10166357244.

It is an arithmetic number, because the mean of its divisors is an integer number (23721500229).

Almost surely, 2^81330857924 is an apocalyptic number.

It is an amenable number.

81330857924 is a deficient number, since it is larger than the sum of its proper divisors (60998143450).

81330857924 is a wasteful number, since it uses less digits than its factorization.

81330857924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20332714485 (or 20332714483 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 50.

The spelling of 81330857924 in words is "eighty-one billion, three hundred thirty million, eight hundred fifty-seven thousand, nine hundred twenty-four".