2158391 has 4 divisors (see below), whose sum is σ = 2188032. Its totient is φ = 2128752.

The previous prime is 2158369. The next prime is 2158393. The reversal of 2158391 is 1938512.

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 2158391 - 2¹⁸ = 1896247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2158393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14711 + ... + 14856.

It is an arithmetic number, because the mean of its divisors is an integer number (547008).

2^2158391 is an apocalyptic number.

2158391 is a deficient number, since it is larger than the sum of its proper divisors (29641).

2158391 is an equidigital number, since it uses as much as digits as its factorization.

2158391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29640.

The product of its digits is 2160, while the sum is 29.

The square root of 2158391 is about 1469.1463507765. The cubic root of 2158391 is about 129.2339763416.

The spelling of 2158391 in words is "two million, one hundred fifty-eight thousand, three hundred ninety-one".