200121209 has 2 divisors, whose sum is σ = 200121210. Its totient is φ = 200121208.

The previous prime is 200121203. The next prime is 200121211. The reversal of 200121209 is 902121002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 196981225 + 3139984 = 14035^2 + 1772^2 .

It is a cyclic number.

It is not a de Polignac number, because 200121209 - 2⁴ = 200121193 is a prime.

Together with 200121211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (200121203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100060604 + 100060605.

It is an arithmetic number, because the mean of its divisors is an integer number (100060605).

Almost surely, 2^200121209 is an apocalyptic number.

It is an amenable number.

200121209 is a deficient number, since it is larger than the sum of its proper divisors (1).

200121209 is an equidigital number, since it uses as much as digits as its factorization.

200121209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 200121209 is about 14146.4203599356. The cubic root of 200121209 is about 584.9216628734.

The spelling of 200121209 in words is "two hundred million, one hundred twenty-one thousand, two hundred nine".