210211210121221 has 4 divisors (see below), whose sum is σ = 210313602334732. Its totient is φ = 210108817907712.

The previous prime is 210211210121197. The next prime is 210211210121239. The reversal of 210211210121221 is 122121012112012.

It is a happy number.

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 47192297212225 + 163018912908996 = 6869665^2 + 12767886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-210211210121221 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 (210211210121821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51196103676 + ... + 51196107781.

It is an arithmetic number, because the mean of its divisors is an integer number (52578400583683).

Almost surely, 2^{210211210121221} is an apocalyptic number.

It is an amenable number.

210211210121221 is a deficient number, since it is larger than the sum of its proper divisors (102392213511).

210211210121221 is a wasteful number, since it uses less digits than its factorization.

210211210121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102392213510.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 210211210121221 its reverse (122121012112012), we get a palindrome (332332222233233).

The spelling of 210211210121221 in words is "two hundred ten trillion, two hundred eleven billion, two hundred ten million, one hundred twenty-one thousand, two hundred twenty-one".