18436694666 has 36 divisors (see below), whose sum is σ = 30809932146. Its totient is φ = 8225165520.

The previous prime is 18436694659. The next prime is 18436694671. The reversal of 18436694666 is 66649663481.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 17727591025 + 709103641 = 133145^2 + 26629^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 21462545 + ... + 21463403.

Almost surely, 2^18436694666 is an apocalyptic number.

18436694666 is a deficient number, since it is larger than the sum of its proper divisors (12373237480).

18436694666 is an frugal number, since it uses more digits than its factorization.

18436694666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1795 (or 905 counting only the distinct ones).

The product of its digits is 26873856, while the sum is 59.

The spelling of 18436694666 in words is "eighteen billion, four hundred thirty-six million, six hundred ninety-four thousand, six hundred sixty-six".