81640623914 has 16 divisors (see below), whose sum is σ = 129670202376. Its totient is φ = 38417433600.

The previous prime is 81640623907. The next prime is 81640623937. The reversal of 81640623914 is 41932604618.

It can be written as a sum of positive squares in 4 ways, for example, as 73920365689 + 7720258225 = 271883^2 + 87865^2 .

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, 1101794 + ... + 1173554.

Almost surely, 2^81640623914 is an apocalyptic number.

81640623914 is a deficient number, since it is larger than the sum of its proper divisors (48029578462).

81640623914 is a wasteful number, since it uses less digits than its factorization.

81640623914 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105241.

The product of its (nonzero) digits is 248832, while the sum is 44.

The spelling of 81640623914 in words is "eighty-one billion, six hundred forty million, six hundred twenty-three thousand, nine hundred fourteen".