21220121002921 has 2 divisors, whose sum is σ = 21220121002922. Its totient is φ = 21220121002920.

The previous prime is 21220121002799. The next prime is 21220121002937. The reversal of 21220121002921 is 12920012102212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11280603712921 + 9939517290000 = 3358661^2 + 3152700^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220121002921 - 2³⁵ = 21185761264553 is a prime.

It is not a weakly prime, because it can be changed into another prime (21220121902921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610060501460 + 10610060501461.

It is an arithmetic number, because the mean of its divisors is an integer number (10610060501461).

Almost surely, 2^{21220121002921} is an apocalyptic number.

It is an amenable number.

21220121002921 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220121002921 is an equidigital number, since it uses as much as digits as its factorization.

21220121002921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 25.

The spelling of 21220121002921 in words is "twenty-one trillion, two hundred twenty billion, one hundred twenty-one million, two thousand, nine hundred twenty-one".