21563231634443 has 2 divisors, whose sum is σ = 21563231634444. Its totient is φ = 21563231634442.

The previous prime is 21563231634383. The next prime is 21563231634521. The reversal of 21563231634443 is 34443613236512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21563231634443 - 2⁸ = 21563231634187 is a prime.

It is not a weakly prime, because it can be changed into another prime (21563231630443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10781615817221 + 10781615817222.

It is an arithmetic number, because the mean of its divisors is an integer number (10781615817222).

Almost surely, 2^{21563231634443} is an apocalyptic number.

21563231634443 is a deficient number, since it is larger than the sum of its proper divisors (1).

21563231634443 is an equidigital number, since it uses as much as digits as its factorization.

21563231634443 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3732480, while the sum is 47.

The spelling of 21563231634443 in words is "twenty-one trillion, five hundred sixty-three billion, two hundred thirty-one million, six hundred thirty-four thousand, four hundred forty-three".