1243391 has 2 divisors, whose sum is σ = 1243392. Its totient is φ = 1243390.

The previous prime is 1243387. The next prime is 1243393. The reversal of 1243391 is 1933421.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1243391 - 2² = 1243387 is a prime.

Together with 1243393, 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 (1243393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621695 + 621696.

It is an arithmetic number, because the mean of its divisors is an integer number (621696).

2^1243391 is an apocalyptic number.

1243391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1243391 is an equidigital number, since it uses as much as digits as its factorization.

1243391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 23.

The square root of 1243391 is about 1115.0744369772. The cubic root of 1243391 is about 107.5315501409.

The spelling of 1243391 in words is "one million, two hundred forty-three thousand, three hundred ninety-one".