11961221 has 2 divisors, whose sum is σ = 11961222. Its totient is φ = 11961220.

The previous prime is 11961211. The next prime is 11961223. The reversal of 11961221 is 12216911.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8916196 + 3045025 = 2986^2 + 1745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11961221 is a prime.

Together with 11961223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11961223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5980610 + 5980611.

It is an arithmetic number, because the mean of its divisors is an integer number (5980611).

Almost surely, 2^11961221 is an apocalyptic number.

It is an amenable number.

11961221 is a deficient number, since it is larger than the sum of its proper divisors (1).

11961221 is an equidigital number, since it uses as much as digits as its factorization.

11961221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 23.

The square root of 11961221 is about 3458.4998192858. The cubic root of 11961221 is about 228.6959664148.

The spelling of 11961221 in words is "eleven million, nine hundred sixty-one thousand, two hundred twenty-one".