210001210021 has 4 divisors (see below), whose sum is σ = 210368988544. Its totient is φ = 209633431500.

The previous prime is 210001209983. The next prime is 210001210049. The reversal of 210001210021 is 120012100012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 210001210021 - 2⁷ = 210001209893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210001210061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 183888405 + ... + 183889546.

It is an arithmetic number, because the mean of its divisors is an integer number (52592247136).

Almost surely, 2^210001210021 is an apocalyptic number.

It is an amenable number.

210001210021 is a deficient number, since it is larger than the sum of its proper divisors (367778523).

210001210021 is an equidigital number, since it uses as much as digits as its factorization.

210001210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367778522.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 210001210021 its reverse (120012100012), we get a palindrome (330013310033).

The spelling of 210001210021 in words is "two hundred ten billion, one million, two hundred ten thousand, twenty-one".