21455303663 has 4 divisors (see below), whose sum is σ = 21491122800. Its totient is φ = 21419484528.

The previous prime is 21455303659. The next prime is 21455303669. The reversal of 21455303663 is 36630355412.

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 21455303663 - 2² = 21455303659 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 (21455303669) 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, 17908670 + ... + 17909867.

It is an arithmetic number, because the mean of its divisors is an integer number (5372780700).

Almost surely, 2^21455303663 is an apocalyptic number.

21455303663 is a deficient number, since it is larger than the sum of its proper divisors (35819137).

21455303663 is an equidigital number, since it uses as much as digits as its factorization.

21455303663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35819136.

The product of its (nonzero) digits is 194400, while the sum is 38.

The spelling of 21455303663 in words is "twenty-one billion, four hundred fifty-five million, three hundred three thousand, six hundred sixty-three".