21003632641 has 2 divisors, whose sum is σ = 21003632642. Its totient is φ = 21003632640.

The previous prime is 21003632627. The next prime is 21003632653. The reversal of 21003632641 is 14623630012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13970294416 + 7033338225 = 118196^2 + 83865^2 .

It is a cyclic number.

It is not a de Polignac number, because 21003632641 - 2⁵ = 21003632609 is a prime.

It is not a weakly prime, because it can be changed into another prime (21003632681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501816320 + 10501816321.

It is an arithmetic number, because the mean of its divisors is an integer number (10501816321).

Almost surely, 2^21003632641 is an apocalyptic number.

It is an amenable number.

21003632641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003632641 is an equidigital number, since it uses as much as digits as its factorization.

21003632641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 28.

The spelling of 21003632641 in words is "twenty-one billion, three million, six hundred thirty-two thousand, six hundred forty-one".