1291331 has 4 divisors (see below), whose sum is σ = 1297200. Its totient is φ = 1285464.

The previous prime is 1291327. The next prime is 1291343. The reversal of 1291331 is 1331921.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1291331 - 2² = 1291327 is a prime.

It is a super-2 number, since 2×1291331² = 3335071503122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1291321) 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, 2591 + ... + 3048.

It is an arithmetic number, because the mean of its divisors is an integer number (324300).

2^1291331 is an apocalyptic number.

1291331 is a deficient number, since it is larger than the sum of its proper divisors (5869).

1291331 is an equidigital number, since it uses as much as digits as its factorization.

1291331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5868.

The product of its digits is 162, while the sum is 20.

The square root of 1291331 is about 1136.3674581754. The cubic root of 1291331 is about 108.8961500009.

The spelling of 1291331 in words is "one million, two hundred ninety-one thousand, three hundred thirty-one".