18663619969 has 4 divisors (see below), whose sum is σ = 19015763796. Its totient is φ = 18311476144.

The previous prime is 18663619937. The next prime is 18663619973. The reversal of 18663619969 is 96991636681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96991636681 = 17 ⋅5705390393.

It can be written as a sum of positive squares in 2 ways, for example, as 8277360400 + 10386259569 = 90980^2 + 101913^2 .

It is a cyclic number.

It is not a de Polignac number, because 18663619969 - 2⁵ = 18663619937 is a prime.

It is a super-3 number, since 3×18663619969³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18663619969.

It is not an unprimeable number, because it can be changed into a prime (18663619979) 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, 176071834 + ... + 176071939.

It is an arithmetic number, because the mean of its divisors is an integer number (4753940949).

Almost surely, 2^18663619969 is an apocalyptic number.

It is an amenable number.

18663619969 is a deficient number, since it is larger than the sum of its proper divisors (352143827).

18663619969 is an equidigital number, since it uses as much as digits as its factorization.

18663619969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352143826.

The product of its digits is 22674816, while the sum is 64.

The spelling of 18663619969 in words is "eighteen billion, six hundred sixty-three million, six hundred nineteen thousand, nine hundred sixty-nine".