18956064991 has 4 divisors (see below), whose sum is σ = 18956565712. Its totient is φ = 18955564272.

The previous prime is 18956064971. The next prime is 18956065013. The reversal of 18956064991 is 19946065981.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18956064991 - 2²¹ = 18953967839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18956064971) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 188475 + ... + 270988.

It is an arithmetic number, because the mean of its divisors is an integer number (4739141428).

Almost surely, 2^18956064991 is an apocalyptic number.

18956064991 is a deficient number, since it is larger than the sum of its proper divisors (500721).

18956064991 is an equidigital number, since it uses as much as digits as its factorization.

18956064991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500720.

The product of its (nonzero) digits is 4199040, while the sum is 58.

The spelling of 18956064991 in words is "eighteen billion, nine hundred fifty-six million, sixty-four thousand, nine hundred ninety-one".