251121 has 16 divisors (see below), whose sum is σ = 370944. Its totient is φ = 150144.

The previous prime is 251117. The next prime is 251143. The reversal of 251121 is 121152.

It is not a de Polignac number, because 251121 - 2² = 251117 is a prime.

It is a super-3 number, since 3×251121³ = 47508394168333683, which contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 251097 and 251106.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 251121.

It is not an unprimeable number, because it can be changed into a prime (251171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1765 + ... + 1901.

It is an arithmetic number, because the mean of its divisors is an integer number (23184).

2²⁵¹¹²¹ is an apocalyptic number.

It is an amenable number.

251121 is a deficient number, since it is larger than the sum of its proper divisors (119823).

251121 is a wasteful number, since it uses less digits than its factorization.

251121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200.

The product of its digits is 20, while the sum is 12.

The square root of 251121 is about 501.1197461685. The cubic root of 251121 is about 63.0900702091.

Adding to 251121 its reverse (121152), we get a palindrome (372273).

The spelling of 251121 in words is "two hundred fifty-one thousand, one hundred twenty-one".