256746491 has 2 divisors, whose sum is σ = 256746492. Its totient is φ = 256746490.

The previous prime is 256746481. The next prime is 256746517. The reversal of 256746491 is 194647652.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256746491 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (256746481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128373245 + 128373246.

It is an arithmetic number, because the mean of its divisors is an integer number (128373246).

Almost surely, 2^256746491 is an apocalyptic number.

256746491 is a deficient number, since it is larger than the sum of its proper divisors (1).

256746491 is an equidigital number, since it uses as much as digits as its factorization.

256746491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 44.

The square root of 256746491 is about 16023.3108626151. The cubic root of 256746491 is about 635.5769992600.

The spelling of 256746491 in words is "two hundred fifty-six million, seven hundred forty-six thousand, four hundred ninety-one".