21002120121013 has 2 divisors, whose sum is σ = 21002120121014. Its totient is φ = 21002120121012.

The previous prime is 21002120121007. The next prime is 21002120121049. The reversal of 21002120121013 is 31012102120012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20974183338564 + 27936782449 = 4579758^2 + 167143^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002120121013 - 2¹³ = 21002120112821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21002120121083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501060060506 + 10501060060507.

It is an arithmetic number, because the mean of its divisors is an integer number (10501060060507).

Almost surely, 2^{21002120121013} is an apocalyptic number.

It is an amenable number.

21002120121013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002120121013 is an equidigital number, since it uses as much as digits as its factorization.

21002120121013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21002120121013 its reverse (31012102120012), we get a palindrome (52014222241025).

The spelling of 21002120121013 in words is "twenty-one trillion, two billion, one hundred twenty million, one hundred twenty-one thousand, thirteen".