256778287 has 4 divisors (see below), whose sum is σ = 256826536. Its totient is φ = 256730040.

The previous prime is 256778273. The next prime is 256778311. The reversal of 256778287 is 782877652.

256778287 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 256778287 - 2¹⁵ = 256745519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256778227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14988 + ... + 27169.

It is an arithmetic number, because the mean of its divisors is an integer number (64206634).

Almost surely, 2^256778287 is an apocalyptic number.

256778287 is a deficient number, since it is larger than the sum of its proper divisors (48249).

256778287 is an equidigital number, since it uses as much as digits as its factorization.

256778287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48248.

The product of its digits is 2634240, while the sum is 52.

The square root of 256778287 is about 16024.3030113637. The cubic root of 256778287 is about 635.6032352201.

The spelling of 256778287 in words is "two hundred fifty-six million, seven hundred seventy-eight thousand, two hundred eighty-seven".