202121202221 has 4 divisors (see below), whose sum is σ = 202224802944. Its totient is φ = 202017601500.

The previous prime is 202121202197. The next prime is 202121202259. The reversal of 202121202221 is 122202121202.

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 a de Polignac number, because none of the positive numbers 2^k-202121202221 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 202121202221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (202121202281) 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, 51797435 + ... + 51801336.

It is an arithmetic number, because the mean of its divisors is an integer number (50556200736).

Almost surely, 2^202121202221 is an apocalyptic number.

It is an amenable number.

202121202221 is a deficient number, since it is larger than the sum of its proper divisors (103600723).

202121202221 is a wasteful number, since it uses less digits than its factorization.

202121202221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103600722.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 202121202221 its reverse (122202121202), we get a palindrome (324323323423).

The spelling of 202121202221 in words is "two hundred two billion, one hundred twenty-one million, two hundred two thousand, two hundred twenty-one".