201220991 has 2 divisors, whose sum is σ = 201220992. Its totient is φ = 201220990.

The previous prime is 201220949. The next prime is 201221003. The reversal of 201220991 is 199022102.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201220991 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 201220991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201220391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610495 + 100610496.

It is an arithmetic number, because the mean of its divisors is an integer number (100610496).

Almost surely, 2^201220991 is an apocalyptic number.

201220991 is a deficient number, since it is larger than the sum of its proper divisors (1).

201220991 is an equidigital number, since it uses as much as digits as its factorization.

201220991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 201220991 is about 14185.2384893593. The cubic root of 201220991 is about 585.9912005031.

The spelling of 201220991 in words is "two hundred one million, two hundred twenty thousand, nine hundred ninety-one".