256699 has 2 divisors, whose sum is σ = 256700. Its totient is φ = 256698.

The previous prime is 256687. The next prime is 256721. The reversal of 256699 is 996652.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256699 - 2⁹ = 256187 is a prime.

It is a d-powerful number, because it can be written as 2¹⁷ + 5⁷ + 6² + 6⁶ + 9² + 9³ .

It is a plaindrome in base 10.

It is a nialpdrome in base 9.

It is not a weakly prime, because it can be changed into another prime (256609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128349 + 128350.

It is an arithmetic number, because the mean of its divisors is an integer number (128350).

2²⁵⁶⁶⁹⁹ is an apocalyptic number.

256699 is a deficient number, since it is larger than the sum of its proper divisors (1).

256699 is an equidigital number, since it uses as much as digits as its factorization.

256699 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29160, while the sum is 37.

The square root of 256699 is about 506.6547147713. The cubic root of 256699 is about 63.5537808788.

It can be divided in two parts, 25 and 6699, that added together give a square (6724 = 82²).

The spelling of 256699 in words is "two hundred fifty-six thousand, six hundred ninety-nine".