21013332121 has 2 divisors, whose sum is σ = 21013332122. Its totient is φ = 21013332120.

The previous prime is 21013332079. The next prime is 21013332127. The reversal of 21013332121 is 12123331012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20431557721 + 581774400 = 142939^2 + 24120^2 .

It is a cyclic number.

It is not a de Polignac number, because 21013332121 - 2⁷ = 21013331993 is a prime.

It is not a weakly prime, because it can be changed into another prime (21013332127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506666060 + 10506666061.

It is an arithmetic number, because the mean of its divisors is an integer number (10506666061).

Almost surely, 2^21013332121 is an apocalyptic number.

It is an amenable number.

21013332121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21013332121 is an equidigital number, since it uses as much as digits as its factorization.

21013332121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21013332121 its reverse (12123331012), we get a palindrome (33136663133).

The spelling of 21013332121 in words is "twenty-one billion, thirteen million, three hundred thirty-two thousand, one hundred twenty-one".