201221002009 has 2 divisors, whose sum is σ = 201221002010. Its totient is φ = 201221002008.

The previous prime is 201221001977. The next prime is 201221002013. The reversal of 201221002009 is 900200122102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 166007353600 + 35213648409 = 407440^2 + 187653^2 .

It is a cyclic number.

It is not a de Polignac number, because 201221002009 - 2⁵ = 201221001977 is a prime.

It is not a weakly prime, because it can be changed into another prime (201221002069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610501004 + 100610501005.

It is an arithmetic number, because the mean of its divisors is an integer number (100610501005).

Almost surely, 2^201221002009 is an apocalyptic number.

It is an amenable number.

201221002009 is a deficient number, since it is larger than the sum of its proper divisors (1).

201221002009 is an equidigital number, since it uses as much as digits as its factorization.

201221002009 is an odious number, because the sum of its binary digits is odd.

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

The spelling of 201221002009 in words is "two hundred one billion, two hundred twenty-one million, two thousand, nine".