1231042391 has 2 divisors, whose sum is σ = 1231042392. Its totient is φ = 1231042390.

The previous prime is 1231042387. The next prime is 1231042441. The reversal of 1231042391 is 1932401321.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1231042391 - 2² = 1231042387 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1231042391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231042381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615521195 + 615521196.

It is an arithmetic number, because the mean of its divisors is an integer number (615521196).

Almost surely, 2^1231042391 is an apocalyptic number.

1231042391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231042391 is an equidigital number, since it uses as much as digits as its factorization.

1231042391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 1231042391 is about 35086.2136885700. The cubic root of 1231042391 is about 1071.7438565152.

The spelling of 1231042391 in words is "one billion, two hundred thirty-one million, forty-two thousand, three hundred ninety-one".