256041509 has 2 divisors, whose sum is σ = 256041510. Its totient is φ = 256041508.

The previous prime is 256041503. The next prime is 256041521. The reversal of 256041509 is 905140652.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 255520225 + 521284 = 15985^2 + 722^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256041509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256041503) 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, 128020754 + 128020755.

It is an arithmetic number, because the mean of its divisors is an integer number (128020755).

Almost surely, 2^256041509 is an apocalyptic number.

It is an amenable number.

256041509 is a deficient number, since it is larger than the sum of its proper divisors (1).

256041509 is an equidigital number, since it uses as much as digits as its factorization.

256041509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 256041509 is about 16001.2971036726. The cubic root of 256041509 is about 634.9947373859.

The spelling of 256041509 in words is "two hundred fifty-six million, forty-one thousand, five hundred nine".