256635493 has 2 divisors, whose sum is σ = 256635494. Its totient is φ = 256635492.

The previous prime is 256635469. The next prime is 256635499. The reversal of 256635493 is 394536652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 256544289 + 91204 = 16017^2 + 302^2 .

It is a cyclic number.

It is not a de Polignac number, because 256635493 - 2⁵ = 256635461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256635499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128317746 + 128317747.

It is an arithmetic number, because the mean of its divisors is an integer number (128317747).

Almost surely, 2^256635493 is an apocalyptic number.

It is an amenable number.

256635493 is a deficient number, since it is larger than the sum of its proper divisors (1).

256635493 is an equidigital number, since it uses as much as digits as its factorization.

256635493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 583200, while the sum is 43.

The square root of 256635493 is about 16019.8468469583. The cubic root of 256635493 is about 635.4853940551.

The spelling of 256635493 in words is "two hundred fifty-six million, six hundred thirty-five thousand, four hundred ninety-three".