210101220121 has 4 divisors (see below), whose sum is σ = 226262852452. Its totient is φ = 193939587792.

The previous prime is 210101220101. The next prime is 210101220127. The reversal of 210101220121 is 121022101012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 62790336400 + 147310883721 = 250580^2 + 383811^2 .

It is a cyclic number.

It is not a de Polignac number, because 210101220121 - 2⁹ = 210101219609 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 16161632317 = 210101220121 / (2 + 1 + 0 + 1 + 0 + 1 + 2 + 2 + 0 + 1 + 2 + 1).

It is not an unprimeable number, because it can be changed into a prime (210101220127) 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, 8080816146 + ... + 8080816171.

It is an arithmetic number, because the mean of its divisors is an integer number (56565713113).

Almost surely, 2^210101220121 is an apocalyptic number.

It is an amenable number.

210101220121 is a deficient number, since it is larger than the sum of its proper divisors (16161632331).

210101220121 is a wasteful number, since it uses less digits than its factorization.

210101220121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16161632330.

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

Adding to 210101220121 its reverse (121022101012), we get a palindrome (331123321133).

The spelling of 210101220121 in words is "two hundred ten billion, one hundred one million, two hundred twenty thousand, one hundred twenty-one".