256133909 has 2 divisors, whose sum is σ = 256133910. Its totient is φ = 256133908.

The previous prime is 256133903. The next prime is 256133921. The reversal of 256133909 is 909331652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 129458884 + 126675025 = 11378^2 + 11255^2 .

It is a cyclic number.

It is not a de Polignac number, because 256133909 - 2⁴ = 256133893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256133903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128066954 + 128066955.

It is an arithmetic number, because the mean of its divisors is an integer number (128066955).

Almost surely, 2^256133909 is an apocalyptic number.

It is an amenable number.

256133909 is a deficient number, since it is larger than the sum of its proper divisors (1).

256133909 is an equidigital number, since it uses as much as digits as its factorization.

256133909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43740, while the sum is 38.

The square root of 256133909 is about 16004.1841091635. The cubic root of 256133909 is about 635.0711136179.

The spelling of 256133909 in words is "two hundred fifty-six million, one hundred thirty-three thousand, nine hundred nine".