251161 has 4 divisors (see below), whose sum is σ = 264400. Its totient is φ = 237924.

The previous prime is 251159. The next prime is 251171. The reversal of 251161 is 161152.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 251161 - 2¹ = 251159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251171) 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, 6591 + ... + 6628.

It is an arithmetic number, because the mean of its divisors is an integer number (66100).

2²⁵¹¹⁶¹ is an apocalyptic number.

It is an amenable number.

251161 is a deficient number, since it is larger than the sum of its proper divisors (13239).

251161 is a wasteful number, since it uses less digits than its factorization.

251161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13238.

The product of its digits is 60, while the sum is 16.

The square root of 251161 is about 501.1596551998. The cubic root of 251161 is about 63.0934198146.

Subtracting from 251161 its reverse (161152), we obtain a palindrome (90009).

The spelling of 251161 in words is "two hundred fifty-one thousand, one hundred sixty-one".