156391 has 4 divisors (see below), whose sum is σ = 160072. Its totient is φ = 152712.

The previous prime is 156371. The next prime is 156419. The reversal of 156391 is 193651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 193651 = 197 ⋅983.

It is a cyclic number.

It is not a de Polignac number, because 156391 - 2¹³ = 148199 is a prime.

It is a Duffinian number.

156391 is a lucky number.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (156361) 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, 1776 + ... + 1861.

It is an arithmetic number, because the mean of its divisors is an integer number (40018).

2¹⁵⁶³⁹¹ is an apocalyptic number.

156391 is a deficient number, since it is larger than the sum of its proper divisors (3681).

156391 is an equidigital number, since it uses as much as digits as its factorization.

156391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3680.

The product of its digits is 810, while the sum is 25.

The square root of 156391 is about 395.4630197629. The cubic root of 156391 is about 53.8770637287.

The spelling of 156391 in words is "one hundred fifty-six thousand, three hundred ninety-one".