21304560663 has 6 divisors (see below), whose sum is σ = 30773254304. Its totient is φ = 14203040436.

The previous prime is 21304560659. The next prime is 21304560709. The reversal of 21304560663 is 36606540312.

21304560663 is a `hidden beast` number, since 2 + 1 + 3 + 0 + 45 + 606 + 6 + 3 = 666.

It is not a de Polignac number, because 21304560663 - 2² = 21304560659 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 (21304560643) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1183586695 + ... + 1183586712.

Almost surely, 2^21304560663 is an apocalyptic number.

21304560663 is a deficient number, since it is larger than the sum of its proper divisors (9468693641).

21304560663 is a wasteful number, since it uses less digits than its factorization.

21304560663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2367173413 (or 2367173410 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

The spelling of 21304560663 in words is "twenty-one billion, three hundred four million, five hundred sixty thousand, six hundred sixty-three".