21220121297 has 2 divisors, whose sum is σ = 21220121298. Its totient is φ = 21220121296.

The previous prime is 21220121203. The next prime is 21220121317. The reversal of 21220121297 is 79212102212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17120152336 + 4099968961 = 130844^2 + 64031^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220121297 - 2²⁴ = 21203344081 is a prime.

It is not a weakly prime, because it can be changed into another prime (21220124297) 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, 10610060648 + 10610060649.

It is an arithmetic number, because the mean of its divisors is an integer number (10610060649).

Almost surely, 2^21220121297 is an apocalyptic number.

It is an amenable number.

21220121297 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220121297 is an equidigital number, since it uses as much as digits as its factorization.

21220121297 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 29.

The spelling of 21220121297 in words is "twenty-one billion, two hundred twenty million, one hundred twenty-one thousand, two hundred ninety-seven".