210021200021 has 4 divisors (see below), whose sum is σ = 210023721600. Its totient is φ = 210018678444.

The previous prime is 210021200017. The next prime is 210021200071. The reversal of 210021200021 is 120002120012.

It is a happy number.

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 210021200021 - 2² = 210021200017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 210021199975 and 210021200011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210021200071) 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, 1131431 + ... + 1303908.

It is an arithmetic number, because the mean of its divisors is an integer number (52505930400).

Almost surely, 2^210021200021 is an apocalyptic number.

It is an amenable number.

210021200021 is a deficient number, since it is larger than the sum of its proper divisors (2521579).

210021200021 is an equidigital number, since it uses as much as digits as its factorization.

210021200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2521578.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 210021200021 its reverse (120002120012), we get a palindrome (330023320033).

The spelling of 210021200021 in words is "two hundred ten billion, twenty-one million, two hundred thousand, twenty-one".