81125993220 has 96 divisors (see below), whose sum is σ = 228620206080. Its totient is φ = 21494125440.

The previous prime is 81125993219. The next prime is 81125993227. The reversal of 81125993220 is 2239952118.

It is not an unprimeable number, because it can be changed into a prime (81125993227) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10527889 + ... + 10535591.

It is an arithmetic number, because the mean of its divisors is an integer number (2381460480).

Almost surely, 2^81125993220 is an apocalyptic number.

It is an amenable number.

81125993220 is an abundant number, since it is smaller than the sum of its proper divisors (147494212860).

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

81125993220 is a wasteful number, since it uses less digits than its factorization.

81125993220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8825 (or 8823 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The spelling of 81125993220 in words is "eighty-one billion, one hundred twenty-five million, nine hundred ninety-three thousand, two hundred twenty".