251321 has 12 divisors (see below), whose sum is σ = 306432. Its totient is φ = 205128.

The previous prime is 251297. The next prime is 251323. The reversal of 251321 is 123152.

It is a happy number.

It is not a de Polignac number, because 251321 - 2⁶ = 251257 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 251296 and 251305.

It is not an unprimeable number, because it can be changed into a prime (251323) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1016 + ... + 1238.

It is an arithmetic number, because the mean of its divisors is an integer number (25536).

2²⁵¹³²¹ is an apocalyptic number.

It is an amenable number.

251321 is a deficient number, since it is larger than the sum of its proper divisors (55111).

251321 is a wasteful number, since it uses less digits than its factorization.

251321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260 (or 253 counting only the distinct ones).

The product of its digits is 60, while the sum is 14.

The square root of 251321 is about 501.3192595542. The cubic root of 251321 is about 63.1068146812.

Adding to 251321 its reverse (123152), we get a palindrome (374473).

The spelling of 251321 in words is "two hundred fifty-one thousand, three hundred twenty-one".