202120409 has 2 divisors, whose sum is σ = 202120410. Its totient is φ = 202120408.

The previous prime is 202120397. The next prime is 202120411. The reversal of 202120409 is 904021202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 167133184 + 34987225 = 12928^2 + 5915^2 .

It is a cyclic number.

It is not a de Polignac number, because 202120409 - 2⁴ = 202120393 is a prime.

It is a Sophie Germain prime.

Together with 202120411, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (202120439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101060204 + 101060205.

It is an arithmetic number, because the mean of its divisors is an integer number (101060205).

Almost surely, 2^202120409 is an apocalyptic number.

It is an amenable number.

202120409 is a deficient number, since it is larger than the sum of its proper divisors (1).

202120409 is an equidigital number, since it uses as much as digits as its factorization.

202120409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 202120409 is about 14216.9057463289. The cubic root of 202120409 is about 586.8629911049.

The spelling of 202120409 in words is "two hundred two million, one hundred twenty thousand, four hundred nine".