2158791 has 4 divisors (see below), whose sum is σ = 2878392. Its totient is φ = 1439192.

The previous prime is 2158781. The next prime is 2158801. The reversal of 2158791 is 1978512.

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

It is an interprime number because it is at equal distance from previous prime (2158781) and next prime (2158801).

It is a cyclic number.

It is not a de Polignac number, because 2158791 - 2⁵ = 2158759 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2158721) 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, 359796 + ... + 359801.

It is an arithmetic number, because the mean of its divisors is an integer number (719598).

2^2158791 is an apocalyptic number.

2158791 is a deficient number, since it is larger than the sum of its proper divisors (719601).

2158791 is an equidigital number, since it uses as much as digits as its factorization.

2158791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 719600.

The product of its digits is 5040, while the sum is 33.

The square root of 2158791 is about 1469.2824779463. The cubic root of 2158791 is about 129.2419592013.

The spelling of 2158791 in words is "two million, one hundred fifty-eight thousand, seven hundred ninety-one".