11871221 has 2 divisors, whose sum is σ = 11871222. Its totient is φ = 11871220.

The previous prime is 11871203. The next prime is 11871227. The reversal of 11871221 is 12217811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9579025 + 2292196 = 3095^2 + 1514^2 .

It is an emirp because it is prime and its reverse (12217811) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11871221 - 2⁶ = 11871157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11871227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5935610 + 5935611.

It is an arithmetic number, because the mean of its divisors is an integer number (5935611).

Almost surely, 2^11871221 is an apocalyptic number.

It is an amenable number.

11871221 is a deficient number, since it is larger than the sum of its proper divisors (1).

11871221 is an equidigital number, since it uses as much as digits as its factorization.

11871221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 224, while the sum is 23.

The square root of 11871221 is about 3445.4638294430. The cubic root of 11871221 is about 228.1209282066.

The spelling of 11871221 in words is "eleven million, eight hundred seventy-one thousand, two hundred twenty-one".