1191221 has 2 divisors, whose sum is σ = 1191222. Its totient is φ = 1191220.

The previous prime is 1191209. The next prime is 1191247. The reversal of 1191221 is 1221911.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1060900 + 130321 = 1030^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 1191221 - 2¹⁸ = 929077 is a prime.

It is a Chen prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 1191221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1191821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 595610 + 595611.

It is an arithmetic number, because the mean of its divisors is an integer number (595611).

2^1191221 is an apocalyptic number.

It is an amenable number.

1191221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1191221 is an equidigital number, since it uses as much as digits as its factorization.

1191221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36, while the sum is 17.

The square root of 1191221 is about 1091.4307124138. The cubic root of 1191221 is about 106.0060812934.

The spelling of 1191221 in words is "one million, one hundred ninety-one thousand, two hundred twenty-one".