202109221 has 4 divisors (see below), whose sum is σ = 202138092. Its totient is φ = 202080352.

The previous prime is 202109203. The next prime is 202109231. The reversal of 202109221 is 122901202.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 123520996 + 78588225 = 11114^2 + 8865^2 .

It is a cyclic number.

It is not a de Polignac number, because 202109221 - 2¹¹ = 202107173 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 (202109231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3465 + ... + 20401.

It is an arithmetic number, because the mean of its divisors is an integer number (50534523).

Almost surely, 2^202109221 is an apocalyptic number.

It is an amenable number.

202109221 is a deficient number, since it is larger than the sum of its proper divisors (28871).

202109221 is a wasteful number, since it uses less digits than its factorization.

202109221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28870.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 202109221 is about 14216.5122656719. The cubic root of 202109221 is about 586.8521626680.

The spelling of 202109221 in words is "two hundred two million, one hundred nine thousand, two hundred twenty-one".