21115664663 has 8 divisors (see below), whose sum is σ = 21798896256. Its totient is φ = 20432563200.

The previous prime is 21115664627. The next prime is 21115664681. The reversal of 21115664663 is 36646651112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21115664663 - 2⁸ = 21115664407 is a prime.

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 21115664663.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115664683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 380795 + ... + 432707.

It is an arithmetic number, because the mean of its divisors is an integer number (2724862032).

Almost surely, 2^21115664663 is an apocalyptic number.

21115664663 is a deficient number, since it is larger than the sum of its proper divisors (683231593).

21115664663 is a wasteful number, since it uses less digits than its factorization.

21115664663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65065.

The product of its digits is 155520, while the sum is 41.

The spelling of 21115664663 in words is "twenty-one billion, one hundred fifteen million, six hundred sixty-four thousand, six hundred sixty-three".