210021311221 has 4 divisors (see below), whose sum is σ = 210379099392. Its totient is φ = 209663523052.

The previous prime is 210021311179. The next prime is 210021311231. The reversal of 210021311221 is 122113120012.

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 a de Polignac number, because none of the positive numbers 2^k-210021311221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 210021311195 and 210021311204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210021311231) 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, 178893205 + ... + 178894378.

It is an arithmetic number, because the mean of its divisors is an integer number (52594774848).

Almost surely, 2^210021311221 is an apocalyptic number.

It is an amenable number.

210021311221 is a deficient number, since it is larger than the sum of its proper divisors (357788171).

210021311221 is an equidigital number, since it uses as much as digits as its factorization.

210021311221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357788170.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 210021311221 its reverse (122113120012), we get a palindrome (332134431233).

The spelling of 210021311221 in words is "two hundred ten billion, twenty-one million, three hundred eleven thousand, two hundred twenty-one".