81689681626 has 16 divisors (see below), whose sum is σ = 140043352896. Its totient is φ = 35008888896.

The previous prime is 81689681581. The next prime is 81689681639. The reversal of 81689681626 is 62618698618.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 696225 + ... + 805051.

It is an arithmetic number, because the mean of its divisors is an integer number (8752709556).

Almost surely, 2^81689681626 is an apocalyptic number.

81689681626 is a deficient number, since it is larger than the sum of its proper divisors (58353671270).

81689681626 is a wasteful number, since it uses less digits than its factorization.

81689681626 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162453.

The product of its digits is 11943936, while the sum is 61.

The spelling of 81689681626 in words is "eighty-one billion, six hundred eighty-nine million, six hundred eighty-one thousand, six hundred twenty-six".