210202121221 has 4 divisors (see below), whose sum is σ = 212283330444. Its totient is φ = 208120912000.

The previous prime is 210202121131. The next prime is 210202121263. The reversal of 210202121221 is 122121202012.

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 166149988225 + 44052132996 = 407615^2 + 209886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-210202121221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 210202121195 and 210202121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210202121821) 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, 1040604460 + ... + 1040604661.

It is an arithmetic number, because the mean of its divisors is an integer number (53070832611).

Almost surely, 2^210202121221 is an apocalyptic number.

It is an amenable number.

210202121221 is a deficient number, since it is larger than the sum of its proper divisors (2081209223).

210202121221 is a wasteful number, since it uses less digits than its factorization.

210202121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2081209222.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 210202121221 its reverse (122121202012), we get a palindrome (332323323233).

The spelling of 210202121221 in words is "two hundred ten billion, two hundred two million, one hundred twenty-one thousand, two hundred twenty-one".