256501 has 4 divisors (see below), whose sum is σ = 293152. Its totient is φ = 219852.

The previous prime is 256499. The next prime is 256517. The reversal of 256501 is 105652.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 256501 - 2¹ = 256499 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256541) 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 3 ways as a sum of consecutive naturals, for example, 18315 + ... + 18328.

It is an arithmetic number, because the mean of its divisors is an integer number (73288).

2²⁵⁶⁵⁰¹ is an apocalyptic number.

It is an amenable number.

256501 is a deficient number, since it is larger than the sum of its proper divisors (36651).

256501 is an equidigital number, since it uses as much as digits as its factorization.

256501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36650.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 256501 is about 506.4592777312. The cubic root of 256501 is about 63.5374363334.

It can be divided in two parts, 25650 and 1, that added together give a triangular number (25651 = T₂₂₆).

The spelling of 256501 in words is "two hundred fifty-six thousand, five hundred one".