21102001202021 has 2 divisors, whose sum is σ = 21102001202022. Its totient is φ = 21102001202020.

The previous prime is 21102001201949. The next prime is 21102001202033. The reversal of 21102001202021 is 12020210020112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16726014165025 + 4375987036996 = 4089745^2 + 2091886^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102001202021 - 2²² = 21101997007717 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21102001201987 and 21102001202005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102001222021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551000601010 + 10551000601011.

It is an arithmetic number, because the mean of its divisors is an integer number (10551000601011).

Almost surely, 2^{21102001202021} is an apocalyptic number.

It is an amenable number.

21102001202021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102001202021 is an equidigital number, since it uses as much as digits as its factorization.

21102001202021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21102001202021 its reverse (12020210020112), we get a palindrome (33122211222133).

The spelling of 21102001202021 in words is "twenty-one trillion, one hundred two billion, one million, two hundred two thousand, twenty-one".