1231091 has 2 divisors, whose sum is σ = 1231092. Its totient is φ = 1231090.

The previous prime is 1231073. The next prime is 1231093. The reversal of 1231091 is 1901321.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1231091 - 2¹⁰ = 1230067 is a prime.

Together with 1231093, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1231093) 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, 615545 + 615546.

It is an arithmetic number, because the mean of its divisors is an integer number (615546).

2^1231091 is an apocalyptic number.

1231091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231091 is an equidigital number, since it uses as much as digits as its factorization.

1231091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54, while the sum is 17.

The square root of 1231091 is about 1109.5454024059. The cubic root of 1231091 is about 107.1757962640.

The spelling of 1231091 in words is "one million, two hundred thirty-one thousand, ninety-one".