256559778 has 64 divisors (see below), whose sum is σ = 588176640. Its totient is φ = 82857600.

The previous prime is 256559777. The next prime is 256559783. The reversal of 256559778 is 877955652.

256559778 is a `hidden beast` number, since 2 + 565 + 5 + 9 + 7 + 78 = 666.

256559778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a fibodiv number, since the Fibonacci-like sequence with seeds 2565 and 59778 contains 256559778 itself.

It is not an unprimeable number, because it can be changed into a prime (256559773) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 233326 + ... + 234422.

It is an arithmetic number, because the mean of its divisors is an integer number (9190260).

Almost surely, 2^256559778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256559778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (294088320).

256559778 is an abundant number, since it is smaller than the sum of its proper divisors (331616862).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256559778 is a wasteful number, since it uses less digits than its factorization.

256559778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1240 (or 1234 counting only the distinct ones).

The product of its digits is 5292000, while the sum is 54.

The square root of 256559778 is about 16017.4835102147. The cubic root of 256559778 is about 635.4228922960.

The spelling of 256559778 in words is "two hundred fifty-six million, five hundred fifty-nine thousand, seven hundred seventy-eight".