21410271221 has 2 divisors, whose sum is σ = 21410271222. Its totient is φ = 21410271220.

The previous prime is 21410271199. The next prime is 21410271247. The reversal of 21410271221 is 12217201412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15973420996 + 5436850225 = 126386^2 + 73735^2 .

It is a cyclic number.

It is not a de Polignac number, because 21410271221 - 2¹⁰ = 21410270197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21410271521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10705135610 + 10705135611.

It is an arithmetic number, because the mean of its divisors is an integer number (10705135611).

Almost surely, 2^21410271221 is an apocalyptic number.

It is an amenable number.

21410271221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21410271221 is an equidigital number, since it uses as much as digits as its factorization.

21410271221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 23.

Adding to 21410271221 its reverse (12217201412), we get a palindrome (33627472633).

The spelling of 21410271221 in words is "twenty-one billion, four hundred ten million, two hundred seventy-one thousand, two hundred twenty-one".