202120209 has 24 divisors (see below), whose sum is σ = 295113000. Its totient is φ = 133297920.

The previous prime is 202120187. The next prime is 202120249. The reversal of 202120209 is 902021202.

It can be written as a sum of positive squares in 4 ways, for example, as 116964225 + 85155984 = 10815^2 + 9228^2 .

It is not a de Polignac number, because 202120209 - 2¹² = 202116113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 202120191 and 202120200.

It is not an unprimeable number, because it can be changed into a prime (202120249) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 578967 + ... + 579315.

It is an arithmetic number, because the mean of its divisors is an integer number (12296375).

Almost surely, 2^202120209 is an apocalyptic number.

It is an amenable number.

202120209 is a deficient number, since it is larger than the sum of its proper divisors (92992791).

202120209 is a wasteful number, since it uses less digits than its factorization.

202120209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 865 (or 862 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 202120209 is about 14216.8987124478. The cubic root of 202120209 is about 586.8627975361.

The spelling of 202120209 in words is "two hundred two million, one hundred twenty thousand, two hundred nine".