256641773 has 2 divisors, whose sum is σ = 256641774. Its totient is φ = 256641772.

The previous prime is 256641769. The next prime is 256641779. The reversal of 256641773 is 377146652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216737284 + 39904489 = 14722^2 + 6317^2 .

It is a cyclic number.

It is not a de Polignac number, because 256641773 - 2² = 256641769 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 256641773.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256641779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128320886 + 128320887.

It is an arithmetic number, because the mean of its divisors is an integer number (128320887).

Almost surely, 2^256641773 is an apocalyptic number.

It is an amenable number.

256641773 is a deficient number, since it is larger than the sum of its proper divisors (1).

256641773 is an equidigital number, since it uses as much as digits as its factorization.

256641773 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 211680, while the sum is 41.

The square root of 256641773 is about 16020.0428526268. The cubic root of 256641773 is about 635.4905775622.

The spelling of 256641773 in words is "two hundred fifty-six million, six hundred forty-one thousand, seven hundred seventy-three".