81197789700 has 72 divisors (see below), whose sum is σ = 235381927648. Its totient is φ = 21611301120.

The previous prime is 81197789693. The next prime is 81197789753. The reversal of 81197789700 is 798779118.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 101857 + ... + 415656.

Almost surely, 2^81197789700 is an apocalyptic number.

It is an amenable number.

81197789700 is an abundant number, since it is smaller than the sum of its proper divisors (154184137948).

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

81197789700 is a wasteful number, since it uses less digits than its factorization.

81197789700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518053 (or 518046 counting only the distinct ones).

The product of its (nonzero) digits is 1778112, while the sum is 57.

The spelling of 81197789700 in words is "eighty-one billion, one hundred ninety-seven million, seven hundred eighty-nine thousand, seven hundred".