249857 has 2 divisors, whose sum is σ = 249858. Its totient is φ = 249856.

The previous prime is 249853. The next prime is 249859. The reversal of 249857 is 758942.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 231361 + 18496 = 481^2 + 136^2 .

It is a cyclic number.

It is not a de Polignac number, because 249857 - 2² = 249853 is a prime.

Together with 249859, it forms a pair of twin primes.

It is a Chen prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 249857.

It is not a weakly prime, because it can be changed into another prime (249853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124928 + 124929.

It is an arithmetic number, because the mean of its divisors is an integer number (124929).

It is a Proth number, since it is equal to 61 ⋅ 2¹² + 1 and 61 < 2¹².

2²⁴⁹⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

249857 is a deficient number, since it is larger than the sum of its proper divisors (1).

249857 is an equidigital number, since it uses as much as digits as its factorization.

249857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 35.

The square root of 249857 is about 499.8569795451. The cubic root of 249857 is about 62.9840389565.

The spelling of 249857 in words is "two hundred forty-nine thousand, eight hundred fifty-seven".