251543 has 2 divisors, whose sum is σ = 251544. Its totient is φ = 251542.

The previous prime is 251539. The next prime is 251561. The reversal of 251543 is 345152.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 251543 - 2² = 251539 is a prime.

It is equal to p₂₂₁₆₉ and since 251543 and 22169 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125771 + 125772.

It is an arithmetic number, because the mean of its divisors is an integer number (125772).

2²⁵¹⁵⁴³ is an apocalyptic number.

251543 is a deficient number, since it is larger than the sum of its proper divisors (1).

251543 is an equidigital number, since it uses as much as digits as its factorization.

251543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 600, while the sum is 20.

The square root of 251543 is about 501.5406264701. The cubic root of 251543 is about 63.1253906456.

Adding to 251543 its reverse (345152), we get a palindrome (596695).

The spelling of 251543 in words is "two hundred fifty-one thousand, five hundred forty-three".