1311389 has 4 divisors (see below), whose sum is σ = 1313820. Its totient is φ = 1308960.

The previous prime is 1311383. The next prime is 1311403. The reversal of 1311389 is 9831131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9831131 = 47 ⋅209173.

It can be written as a sum of positive squares in 2 ways, for example, as 1085764 + 225625 = 1042^2 + 475^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1311389 is a prime.

It is a super-2 number, since 2×1311389² = 3439482218642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311383) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2 + ... + 1619.

It is an arithmetic number, because the mean of its divisors is an integer number (328455).

2^1311389 is an apocalyptic number.

It is an amenable number.

1311389 is a deficient number, since it is larger than the sum of its proper divisors (2431).

1311389 is an equidigital number, since it uses as much as digits as its factorization.

1311389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2430.

The product of its digits is 648, while the sum is 26.

The square root of 1311389 is about 1145.1589409335. The cubic root of 1311389 is about 109.4570767874.

The spelling of 1311389 in words is "one million, three hundred eleven thousand, three hundred eighty-nine".