256694209 has 4 divisors (see below), whose sum is σ = 256746240. Its totient is φ = 256642180.

The previous prime is 256694201. The next prime is 256694233. The reversal of 256694209 is 902496652.

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 256694209 - 2³ = 256694201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256694201) 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, 17737 + ... + 28774.

It is an arithmetic number, because the mean of its divisors is an integer number (64186560).

Almost surely, 2^256694209 is an apocalyptic number.

It is an amenable number.

256694209 is a deficient number, since it is larger than the sum of its proper divisors (52031).

256694209 is an equidigital number, since it uses as much as digits as its factorization.

256694209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52030.

The product of its (nonzero) digits is 233280, while the sum is 43.

The square root of 256694209 is about 16021.6793439389. The cubic root of 256694209 is about 635.5338548956.

The spelling of 256694209 in words is "two hundred fifty-six million, six hundred ninety-four thousand, two hundred nine".