21130432021 has 2 divisors, whose sum is σ = 21130432022. Its totient is φ = 21130432020.

The previous prime is 21130432007. The next prime is 21130432033. The reversal of 21130432021 is 12023403112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19428456996 + 1701975025 = 139386^2 + 41255^2 .

It is a cyclic number.

It is not a de Polignac number, because 21130432021 - 2⁵ = 21130431989 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21130432021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21130432091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565216010 + 10565216011.

It is an arithmetic number, because the mean of its divisors is an integer number (10565216011).

Almost surely, 2^21130432021 is an apocalyptic number.

It is an amenable number.

21130432021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21130432021 is an equidigital number, since it uses as much as digits as its factorization.

21130432021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21130432021 its reverse (12023403112), we get a palindrome (33153835133).

The spelling of 21130432021 in words is "twenty-one billion, one hundred thirty million, four hundred thirty-two thousand, twenty-one".