81611372836 has 24 divisors (see below), whose sum is σ = 166695572736. Its totient is φ = 34232125440.

The previous prime is 81611372783. The next prime is 81611372839. The reversal of 81611372836 is 63827311618.

It is not an unprimeable number, because it can be changed into a prime (81611372839) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31006045 + ... + 31008676.

It is an arithmetic number, because the mean of its divisors is an integer number (6945648864).

Almost surely, 2^81611372836 is an apocalyptic number.

It is an amenable number.

81611372836 is an abundant number, since it is smaller than the sum of its proper divisors (85084199900).

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

81611372836 is a wasteful number, since it uses less digits than its factorization.

81611372836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62014779 (or 62014777 counting only the distinct ones).

The product of its digits is 290304, while the sum is 46.

The spelling of 81611372836 in words is "eighty-one billion, six hundred eleven million, three hundred seventy-two thousand, eight hundred thirty-six".