201221002261 has 2 divisors, whose sum is σ = 201221002262. Its totient is φ = 201221002260.

The previous prime is 201221002249. The next prime is 201221002277. The reversal of 201221002261 is 162200122102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 194806594161 + 6414408100 = 441369^2 + 80090^2 .

It is a cyclic number.

It is not a de Polignac number, because 201221002261 - 2³³ = 192631067669 is a prime.

It is a super-2 number, since 2×201221002261² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201221002361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610501130 + 100610501131.

It is an arithmetic number, because the mean of its divisors is an integer number (100610501131).

Almost surely, 2^201221002261 is an apocalyptic number.

It is an amenable number.

201221002261 is a deficient number, since it is larger than the sum of its proper divisors (1).

201221002261 is an equidigital number, since it uses as much as digits as its factorization.

201221002261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 201221002261 its reverse (162200122102), we get a palindrome (363421124363).

The spelling of 201221002261 in words is "two hundred one billion, two hundred twenty-one million, two thousand, two hundred sixty-one".