256513 has 8 divisors (see below), whose sum is σ = 276480. Its totient is φ = 237120.

The previous prime is 256499. The next prime is 256517. The reversal of 256513 is 315652.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 256513 - 2¹⁷ = 125441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256517) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1248 + ... + 1438.

It is an arithmetic number, because the mean of its divisors is an integer number (34560).

It is a Proth number, since it is equal to 501 ⋅ 2⁹ + 1 and 501 < 2⁹.

2²⁵⁶⁵¹³ is an apocalyptic number.

It is an amenable number.

256513 is a deficient number, since it is larger than the sum of its proper divisors (19967).

256513 is a wasteful number, since it uses less digits than its factorization.

256513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287.

The product of its digits is 900, while the sum is 22.

The square root of 256513 is about 506.4711245471. The cubic root of 256513 is about 63.5384271513.

It can be divided in two parts, 256 and 513, that multiplied together give a triangular number (131328 = T₅₁₂).

The spelling of 256513 in words is "two hundred fifty-six thousand, five hundred thirteen".