202121221 has 4 divisors (see below), whose sum is σ = 212759200. Its totient is φ = 191483244.

The previous prime is 202121219. The next prime is 202121233. The reversal of 202121221 is 122121202.

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 not a de Polignac number, because 202121221 - 2¹ = 202121219 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 (202121321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5318961 + ... + 5318998.

It is an arithmetic number, because the mean of its divisors is an integer number (53189800).

Almost surely, 2^202121221 is an apocalyptic number.

It is an amenable number.

202121221 is a deficient number, since it is larger than the sum of its proper divisors (10637979).

202121221 is a wasteful number, since it uses less digits than its factorization.

202121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10637978.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 202121221 is about 14216.9343038505. The cubic root of 202121221 is about 586.8637769931.

Adding to 202121221 its reverse (122121202), we get a palindrome (324242423).

The spelling of 202121221 in words is "two hundred two million, one hundred twenty-one thousand, two hundred twenty-one".