18661355968 has 28 divisors (see below), whose sum is σ = 37729835640. Its totient is φ = 9154625792.

The previous prime is 18661355953. The next prime is 18661356013. The reversal of 18661355968 is 86955316681.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2747398 + ... + 2754181.

It is an arithmetic number, because the mean of its divisors is an integer number (1347494130).

Almost surely, 2^18661355968 is an apocalyptic number.

It is an amenable number.

18661355968 is an abundant number, since it is smaller than the sum of its proper divisors (19068479672).

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

18661355968 is an equidigital number, since it uses as much as digits as its factorization.

18661355968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5501644 (or 5501634 counting only the distinct ones).

The product of its digits is 9331200, while the sum is 58.

The spelling of 18661355968 in words is "eighteen billion, six hundred sixty-one million, three hundred fifty-five thousand, nine hundred sixty-eight".