251155 has 4 divisors (see below), whose sum is σ = 301392. Its totient is φ = 200920.

The previous prime is 251149. The next prime is 251159. The reversal of 251155 is 551152.

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

It is not a de Polignac number, because 251155 - 2⁹ = 250643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251159) 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, 25111 + ... + 25120.

It is an arithmetic number, because the mean of its divisors is an integer number (75348).

2²⁵¹¹⁵⁵ is an apocalyptic number.

251155 is a deficient number, since it is larger than the sum of its proper divisors (50237).

251155 is an equidigital number, since it uses as much as digits as its factorization.

251155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50236.

The product of its digits is 250, while the sum is 19.

The square root of 251155 is about 501.1536690477. The cubic root of 251155 is about 63.0929173964.

It can be divided in two parts, 251 and 155, that added together give a triangular number (406 = T₂₈).

The spelling of 251155 in words is "two hundred fifty-one thousand, one hundred fifty-five".