11957221 has 2 divisors, whose sum is σ = 11957222. Its totient is φ = 11957220.

The previous prime is 11957219. The next prime is 11957249. The reversal of 11957221 is 12275911.

It is an a-pointer prime, because the next prime (11957249) can be obtained adding 11957221 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9084196 + 2873025 = 3014^2 + 1695^2 .

It is an emirp because it is prime and its reverse (12275911) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11957221 - 2¹ = 11957219 is a prime.

Together with 11957219, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 11957221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11957201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5978610 + 5978611.

It is an arithmetic number, because the mean of its divisors is an integer number (5978611).

Almost surely, 2^11957221 is an apocalyptic number.

It is an amenable number.

11957221 is a deficient number, since it is larger than the sum of its proper divisors (1).

11957221 is an equidigital number, since it uses as much as digits as its factorization.

11957221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1260, while the sum is 28.

The square root of 11957221 is about 3457.9214855170. The cubic root of 11957221 is about 228.6704705267.

The spelling of 11957221 in words is "eleven million, nine hundred fifty-seven thousand, two hundred twenty-one".