21130403221 has 2 divisors, whose sum is σ = 21130403222. Its totient is φ = 21130403220.

The previous prime is 21130403219. The next prime is 21130403227. The reversal of 21130403221 is 12230403112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12502594225 + 8627808996 = 111815^2 + 92886^2 .

It is a cyclic number.

It is not a de Polignac number, because 21130403221 - 2¹ = 21130403219 is a prime.

Together with 21130403219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21130403227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565201610 + 10565201611.

It is an arithmetic number, because the mean of its divisors is an integer number (10565201611).

Almost surely, 2^21130403221 is an apocalyptic number.

It is an amenable number.

21130403221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21130403221 is an equidigital number, since it uses as much as digits as its factorization.

21130403221 is an evil number, because the sum of its binary digits is even.

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

Adding to 21130403221 its reverse (12230403112), we get a palindrome (33360806333).

The spelling of 21130403221 in words is "twenty-one billion, one hundred thirty million, four hundred three thousand, two hundred twenty-one".