201221121917 has 2 divisors, whose sum is σ = 201221121918. Its totient is φ = 201221121916.

The previous prime is 201221121901. The next prime is 201221122007. The reversal of 201221121917 is 719121122102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198618183556 + 2602938361 = 445666^2 + 51019^2 .

It is a cyclic number.

It is not a de Polignac number, because 201221121917 - 2⁴ = 201221121901 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 201221121917.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201221121317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610560958 + 100610560959.

It is an arithmetic number, because the mean of its divisors is an integer number (100610560959).

Almost surely, 2^201221121917 is an apocalyptic number.

It is an amenable number.

201221121917 is a deficient number, since it is larger than the sum of its proper divisors (1).

201221121917 is an equidigital number, since it uses as much as digits as its factorization.

201221121917 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 29.

The spelling of 201221121917 in words is "two hundred one billion, two hundred twenty-one million, one hundred twenty-one thousand, nine hundred seventeen".