256635 has 16 divisors (see below), whose sum is σ = 456480. Its totient is φ = 136800.

The previous prime is 256609. The next prime is 256639. The reversal of 256635 is 536652.

256635 is a `hidden beast` number, since 25 + 6 + 635 = 666.

It is not a de Polignac number, because 256635 - 2⁵ = 256603 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a d-powerful number, because it can be written as 2⁹ + 5⁷ + 6⁶ + 6⁶ + 3⁸ + 5⁷ .

256635 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 256599 and 256608.

It is not an unprimeable number, because it can be changed into a prime (256639) 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 in 15 ways as a sum of consecutive naturals, for example, 816 + ... + 1085.

It is an arithmetic number, because the mean of its divisors is an integer number (28530).

2²⁵⁶⁶³⁵ is an apocalyptic number.

256635 is a deficient number, since it is larger than the sum of its proper divisors (199845).

256635 is a wasteful number, since it uses less digits than its factorization.

256635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1915 (or 1909 counting only the distinct ones).

The product of its digits is 5400, while the sum is 27.

The square root of 256635 is about 506.5915514495. The cubic root of 256635 is about 63.5484987130.

It can be divided in two parts, 2566 and 35, that added together give a square (2601 = 51²).

The spelling of 256635 in words is "two hundred fifty-six thousand, six hundred thirty-five".