256601 has 4 divisors (see below), whose sum is σ = 258612. Its totient is φ = 254592.

The previous prime is 256589. The next prime is 256603. The reversal of 256601 is 106652.

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 63001 + 193600 = 251^2 + 440^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256601 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (256603) 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, 800 + ... + 1073.

It is an arithmetic number, because the mean of its divisors is an integer number (64653).

2²⁵⁶⁶⁰¹ is an apocalyptic number.

It is an amenable number.

256601 is a deficient number, since it is larger than the sum of its proper divisors (2011).

256601 is a wasteful number, since it uses less digits than its factorization.

256601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2010.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 256601 is about 506.5579927313. The cubic root of 256601 is about 63.5456922052.

It can be divided in two parts, 25 and 6601, that multiplied together give a triangular number (165025 = T₅₇₄).

The spelling of 256601 in words is "two hundred fifty-six thousand, six hundred one".