1331591 has 2 divisors, whose sum is σ = 1331592. Its totient is φ = 1331590.

The previous prime is 1331587. The next prime is 1331597. The reversal of 1331591 is 1951331.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1331591 - 2² = 1331587 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1331597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665795 + 665796.

It is an arithmetic number, because the mean of its divisors is an integer number (665796).

2^1331591 is an apocalyptic number.

1331591 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331591 is an equidigital number, since it uses as much as digits as its factorization.

1331591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 405, while the sum is 23.

The square root of 1331591 is about 1153.9458392836. The cubic root of 1331591 is about 110.0162785826.

The spelling of 1331591 in words is "one million, three hundred thirty-one thousand, five hundred ninety-one".