256746209 has 2 divisors, whose sum is σ = 256746210. Its totient is φ = 256746208.

The previous prime is 256746199. The next prime is 256746241. The reversal of 256746209 is 902647652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 253701184 + 3045025 = 15928^2 + 1745^2 .

It is a cyclic number.

It is not a de Polignac number, because 256746209 - 2¹⁶ = 256680673 is a prime.

It is not a weakly prime, because it can be changed into another prime (256746299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128373104 + 128373105.

It is an arithmetic number, because the mean of its divisors is an integer number (128373105).

Almost surely, 2^256746209 is an apocalyptic number.

It is an amenable number.

256746209 is a deficient number, since it is larger than the sum of its proper divisors (1).

256746209 is an equidigital number, since it uses as much as digits as its factorization.

256746209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 181440, while the sum is 41.

The square root of 256746209 is about 16023.3020629332. The cubic root of 256746209 is about 635.5767665625.

It can be divided in two parts, 2567 and 46209, that multiplied together give a triangular number (118618503 = T₁₅₄₀₂).

The spelling of 256746209 in words is "two hundred fifty-six million, seven hundred forty-six thousand, two hundred nine".