256217 has 4 divisors (see below), whose sum is σ = 275940. Its totient is φ = 236496.

The previous prime is 256211. The next prime is 256219. The reversal of 256217 is 712652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 80656 + 175561 = 284^2 + 419^2 .

It is not a de Polignac number, because 256217 - 2⁸ = 255961 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 8.

It is a junction number, because it is equal to n+sod(n) for n = 256192 and 256201.

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 256217.

It is not an unprimeable number, because it can be changed into a prime (256211) 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 3 ways as a sum of consecutive naturals, for example, 9842 + ... + 9867.

It is an arithmetic number, because the mean of its divisors is an integer number (68985).

2²⁵⁶²¹⁷ is an apocalyptic number.

It is an amenable number.

256217 is a deficient number, since it is larger than the sum of its proper divisors (19723).

256217 is a wasteful number, since it uses less digits than its factorization.

256217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19722.

The product of its digits is 840, while the sum is 23.

The square root of 256217 is about 506.1788221568. The cubic root of 256217 is about 63.5139779508.

Adding to 256217 its reverse (712652), we get a palindrome (968869).

The spelling of 256217 in words is "two hundred fifty-six thousand, two hundred seventeen".