256549109 has 4 divisors (see below), whose sum is σ = 265395660. Its totient is φ = 247702560.

The previous prime is 256549067. The next prime is 256549121. The reversal of 256549109 is 901945652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 67404100 + 189145009 = 8210^2 + 13753^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256549109 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256549129) 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, 4423232 + ... + 4423289.

It is an arithmetic number, because the mean of its divisors is an integer number (66348915).

Almost surely, 2^256549109 is an apocalyptic number.

256549109 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

256549109 is a deficient number, since it is larger than the sum of its proper divisors (8846551).

256549109 is an equidigital number, since it uses as much as digits as its factorization.

256549109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8846550.

The product of its (nonzero) digits is 97200, while the sum is 41.

The square root of 256549109 is about 16017.1504644241. The cubic root of 256549109 is about 635.4140841853.

The spelling of 256549109 in words is "two hundred fifty-six million, five hundred forty-nine thousand, one hundred nine".