256787 has 4 divisors (see below), whose sum is σ = 258216. Its totient is φ = 255360.

The previous prime is 256771. The next prime is 256799. The reversal of 256787 is 787652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 256787 - 2⁴ = 256771 is a prime.

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

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 256787.

It is not an unprimeable number, because it can be changed into a prime (256757) 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, 398 + ... + 819.

It is an arithmetic number, because the mean of its divisors is an integer number (64554).

2²⁵⁶⁷⁸⁷ is an apocalyptic number.

256787 is a deficient number, since it is larger than the sum of its proper divisors (1429).

256787 is a wasteful number, since it uses less digits than its factorization.

256787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1428.

The product of its digits is 23520, while the sum is 35.

The square root of 256787 is about 506.7415514836. The cubic root of 256787 is about 63.5610424234.

The spelling of 256787 in words is "two hundred fifty-six thousand, seven hundred eighty-seven".