256843109 has 4 divisors (see below), whose sum is σ = 262307904. Its totient is φ = 251378316.

The previous prime is 256843087. The next prime is 256843117. The reversal of 256843109 is 901348652.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 256843109 - 2⁸ = 256842853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256843129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2732327 + ... + 2732420.

It is an arithmetic number, because the mean of its divisors is an integer number (65576976).

Almost surely, 2^256843109 is an apocalyptic number.

It is an amenable number.

256843109 is a deficient number, since it is larger than the sum of its proper divisors (5464795).

256843109 is an equidigital number, since it uses as much as digits as its factorization.

256843109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5464794.

The product of its (nonzero) digits is 51840, while the sum is 38.

The square root of 256843109 is about 16026.3254990032. The cubic root of 256843109 is about 635.6567153474.

The spelling of 256843109 in words is "two hundred fifty-six million, eight hundred forty-three thousand, one hundred nine".