1591391 has 2 divisors, whose sum is σ = 1591392. Its totient is φ = 1591390.

The previous prime is 1591367. The next prime is 1591397. The reversal of 1591391 is 1931951.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1591391 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1591397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 795695 + 795696.

It is an arithmetic number, because the mean of its divisors is an integer number (795696).

2^1591391 is an apocalyptic number.

1591391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1591391 is an equidigital number, since it uses as much as digits as its factorization.

1591391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1215, while the sum is 29.

The square root of 1591391 is about 1261.5034680888. The cubic root of 1591391 is about 116.7505582557.

The spelling of 1591391 in words is "one million, five hundred ninety-one thousand, three hundred ninety-one".