21260202121 has 2 divisors, whose sum is σ = 21260202122. Its totient is φ = 21260202120.

The previous prime is 21260202113. The next prime is 21260202127. The reversal of 21260202121 is 12120206212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15391876096 + 5868326025 = 124064^2 + 76605^2 .

It is a cyclic number.

It is not a de Polignac number, because 21260202121 - 2³ = 21260202113 is a prime.

It is not a weakly prime, because it can be changed into another prime (21260202127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630101060 + 10630101061.

It is an arithmetic number, because the mean of its divisors is an integer number (10630101061).

Almost surely, 2^21260202121 is an apocalyptic number.

It is an amenable number.

21260202121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21260202121 is an equidigital number, since it uses as much as digits as its factorization.

21260202121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21260202121 its reverse (12120206212), we get a palindrome (33380408333).

The spelling of 21260202121 in words is "twenty-one billion, two hundred sixty million, two hundred two thousand, one hundred twenty-one".