210021021100021 has 2 divisors, whose sum is σ = 210021021100022. Its totient is φ = 210021021100020.

The previous prime is 210021021100013. The next prime is 210021021100043. The reversal of 210021021100021 is 120001120120012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 209279303987121 + 741717112900 = 14466489^2 + 861230^2 .

It is a cyclic number.

It is not a de Polignac number, because 210021021100021 - 2³ = 210021021100013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 210021021099974 and 210021021100010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (210021021100061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105010510550010 + 105010510550011.

It is an arithmetic number, because the mean of its divisors is an integer number (105010510550011).

Almost surely, 2^{210021021100021} is an apocalyptic number.

It is an amenable number.

210021021100021 is a deficient number, since it is larger than the sum of its proper divisors (1).

210021021100021 is an equidigital number, since it uses as much as digits as its factorization.

210021021100021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 210021021100021 its reverse (120001120120012), we get a palindrome (330022141220033).

The spelling of 210021021100021 in words is "two hundred ten trillion, twenty-one billion, twenty-one million, one hundred thousand, twenty-one".