1331391 has 8 divisors (see below), whose sum is σ = 1782144. Its totient is φ = 884120.

The previous prime is 1331383. The next prime is 1331399. The reversal of 1331391 is 1931331.

It is an interprime number because it is at equal distance from previous prime (1331383) and next prime (1331399).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1331391 - 2³ = 1331383 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331399) 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 in 7 ways as a sum of consecutive naturals, for example, 220 + ... + 1646.

It is an arithmetic number, because the mean of its divisors is an integer number (222768).

2^1331391 is an apocalyptic number.

1331391 is a deficient number, since it is larger than the sum of its proper divisors (450753).

1331391 is a wasteful number, since it uses less digits than its factorization.

1331391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1741.

The product of its digits is 243, while the sum is 21.

The square root of 1331391 is about 1153.8591768496. The cubic root of 1331391 is about 110.0107702953.

The spelling of 1331391 in words is "one million, three hundred thirty-one thousand, three hundred ninety-one".