256400017 has 12 divisors (see below), whose sum is σ = 264654340. Its totient is φ = 248355072.

The previous prime is 256400009. The next prime is 256400029. The reversal of 256400017 is 710004652.

It can be written as a sum of positive squares in 2 ways, for example, as 111534721 + 144865296 = 10561^2 + 12036^2 .

It is not a de Polignac number, because 256400017 - 2³ = 256400009 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 256399964 and 256400000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256400057) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 253609 + ... + 254617.

Almost surely, 2^256400017 is an apocalyptic number.

It is an amenable number.

256400017 is a deficient number, since it is larger than the sum of its proper divisors (8254323).

256400017 is an equidigital number, since it uses as much as digits as its factorization.

256400017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1200 (or 1141 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 256400017 is about 16012.4956518339. The cubic root of 256400017 is about 635.2909712856.

Adding to 256400017 its reverse (710004652), we get a palindrome (966404669).

The spelling of 256400017 in words is "two hundred fifty-six million, four hundred thousand, seventeen".