155791 has 4 divisors (see below), whose sum is σ = 157752. Its totient is φ = 153832.

The previous prime is 155783. The next prime is 155797. The reversal of 155791 is 197551.

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 155791 - 2³ = 155783 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 (155797) 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, 856 + ... + 1021.

It is an arithmetic number, because the mean of its divisors is an integer number (39438).

2¹⁵⁵⁷⁹¹ is an apocalyptic number.

155791 is a deficient number, since it is larger than the sum of its proper divisors (1961).

155791 is an equidigital number, since it uses as much as digits as its factorization.

155791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1960.

The product of its digits is 1575, while the sum is 28.

The square root of 155791 is about 394.7036863268. The cubic root of 155791 is about 53.8080749616.

It can be divided in two parts, 155 and 791, that added together give a triangular number (946 = T₄₃).

The spelling of 155791 in words is "one hundred fifty-five thousand, seven hundred ninety-one".