21333120121 has 2 divisors, whose sum is σ = 21333120122. Its totient is φ = 21333120120.

The previous prime is 21333120101. The next prime is 21333120169. The reversal of 21333120121 is 12102133312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17065764496 + 4267355625 = 130636^2 + 65325^2 .

It is a cyclic number.

It is not a de Polignac number, because 21333120121 - 2²⁷ = 21198902393 is a prime.

It is not a weakly prime, because it can be changed into another prime (21333120101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10666560060 + 10666560061.

It is an arithmetic number, because the mean of its divisors is an integer number (10666560061).

Almost surely, 2^21333120121 is an apocalyptic number.

It is an amenable number.

21333120121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21333120121 is an equidigital number, since it uses as much as digits as its factorization.

21333120121 is an evil number, because the sum of its binary digits is even.

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

Adding to 21333120121 its reverse (12102133312), we get a palindrome (33435253433).

The spelling of 21333120121 in words is "twenty-one billion, three hundred thirty-three million, one hundred twenty thousand, one hundred twenty-one".