2191261 has 2 divisors, whose sum is σ = 2191262. Its totient is φ = 2191260.

The previous prime is 2191247. The next prime is 2191291. The reversal of 2191261 is 1621912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1425636 + 765625 = 1194^2 + 875^2 .

It is a cyclic number.

It is not a de Polignac number, because 2191261 - 2⁵ = 2191229 is a prime.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2191291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1095630 + 1095631.

It is an arithmetic number, because the mean of its divisors is an integer number (1095631).

2^2191261 is an apocalyptic number.

It is an amenable number.

2191261 is a deficient number, since it is larger than the sum of its proper divisors (1).

2191261 is an equidigital number, since it uses as much as digits as its factorization.

2191261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 22.

The square root of 2191261 is about 1480.2908497995. The cubic root of 2191261 is about 129.8867060276.

The spelling of 2191261 in words is "two million, one hundred ninety-one thousand, two hundred sixty-one".