256641 has 24 divisors (see below), whose sum is σ = 434112. Its totient is φ = 132000.

The previous prime is 256639. The next prime is 256643. The reversal of 256641 is 146652.

256641 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (256639) and next prime (256643).

It is not a de Polignac number, because 256641 - 2¹ = 256639 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (256643) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2491 + ... + 2591.

It is an arithmetic number, because the mean of its divisors is an integer number (18088).

2²⁵⁶⁶⁴¹ is an apocalyptic number.

256641 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

256641 is a deficient number, since it is larger than the sum of its proper divisors (177471).

256641 is a wasteful number, since it uses less digits than its factorization.

256641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 122 counting only the distinct ones).

The product of its digits is 1440, while the sum is 24.

The square root of 256641 is about 506.5974733455. The cubic root of 256641 is about 63.5489939533.

It can be divided in two parts, 25 and 6641, that added together give a palindrome (6666).

The spelling of 256641 in words is "two hundred fifty-six thousand, six hundred forty-one".