81598819878 has 40 divisors (see below), whose sum is σ = 185570806872. Its totient is φ = 26793638784.

The previous prime is 81598819849. The next prime is 81598819921. The reversal of 81598819878 is 87891889518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3748075 + ... + 3769782.

Almost surely, 2^81598819878 is an apocalyptic number.

81598819878 is an abundant number, since it is smaller than the sum of its proper divisors (103971986994).

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

81598819878 is a wasteful number, since it uses less digits than its factorization.

81598819878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7517938 (or 7517929 counting only the distinct ones).

The product of its digits is 92897280, while the sum is 72.

The spelling of 81598819878 in words is "eighty-one billion, five hundred ninety-eight million, eight hundred nineteen thousand, eight hundred seventy-eight".