256809365 has 8 divisors (see below), whose sum is σ = 308257368. Its totient is φ = 205390080.

The previous prime is 256809353. The next prime is 256809391. The reversal of 256809365 is 563908652.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 521284 + 256288081 = 722^2 + 16009^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 256809365 - 2²⁰ = 255760789 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30185 + ... + 37745.

It is an arithmetic number, because the mean of its divisors is an integer number (38532171).

Almost surely, 2^256809365 is an apocalyptic number.

It is an amenable number.

256809365 is a deficient number, since it is larger than the sum of its proper divisors (51448003).

256809365 is an equidigital number, since it uses as much as digits as its factorization.

256809365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14359.

The product of its (nonzero) digits is 388800, while the sum is 44.

The square root of 256809365 is about 16025.2726965877. The cubic root of 256809365 is about 635.6288766411.

The spelling of 256809365 in words is "two hundred fifty-six million, eight hundred nine thousand, three hundred sixty-five".