81131859232 has 24 divisors (see below), whose sum is σ = 163442963376. Its totient is φ = 39622535232.

The previous prime is 81131859229. The next prime is 81131859239. The reversal of 81131859232 is 23295813118.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is not an unprimeable number, because it can be changed into a prime (81131859239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29479678 + ... + 29482429.

It is an arithmetic number, because the mean of its divisors is an integer number (6810123474).

Almost surely, 2^81131859232 is an apocalyptic number.

It is an amenable number.

81131859232 is an abundant number, since it is smaller than the sum of its proper divisors (82311104144).

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

81131859232 is a wasteful number, since it uses less digits than its factorization.

81131859232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58962160 (or 58962152 counting only the distinct ones).

The product of its digits is 103680, while the sum is 43.

The spelling of 81131859232 in words is "eighty-one billion, one hundred thirty-one million, eight hundred fifty-nine thousand, two hundred thirty-two".