256778766 has 48 divisors (see below), whose sum is σ = 586579968. Its totient is φ = 81061200.

The previous prime is 256778759. The next prime is 256778783. The reversal of 256778766 is 667877652.

256778766 is a `hidden beast` number, since 2 + 567 + 7 + 8 + 76 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 21331 + ... + 31121.

It is an arithmetic number, because the mean of its divisors is an integer number (12220416).

Almost surely, 2^256778766 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256778766, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (293289984).

256778766 is an abundant number, since it is smaller than the sum of its proper divisors (329801202).

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

256778766 is a wasteful number, since it uses less digits than its factorization.

256778766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9877 (or 9874 counting only the distinct ones).

The product of its digits is 5927040, while the sum is 54.

The square root of 256778766 is about 16024.3179574046. The cubic root of 256778766 is about 635.6036304427.

It can be divided in two parts, 25677 and 8766, that added together give a palindrome (34443).

The spelling of 256778766 in words is "two hundred fifty-six million, seven hundred seventy-eight thousand, seven hundred sixty-six".