81606662199 has 12 divisors (see below), whose sum is σ = 117880019712. Its totient is φ = 54402720000.

The previous prime is 81606662153. The next prime is 81606662201. The reversal of 81606662199 is 99126660618.

It is a happy number.

It is not a de Polignac number, because 81606662199 - 2²⁵ = 81573107767 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81606662119) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 200074 + ... + 450824.

It is an arithmetic number, because the mean of its divisors is an integer number (9823334976).

Almost surely, 2^81606662199 is an apocalyptic number.

81606662199 is a deficient number, since it is larger than the sum of its proper divisors (36273357513).

81606662199 is a wasteful number, since it uses less digits than its factorization.

81606662199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286918 (or 286915 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 54.

The spelling of 81606662199 in words is "eighty-one billion, six hundred six million, six hundred sixty-two thousand, one hundred ninety-nine".