256636241 has 2 divisors, whose sum is σ = 256636242. Its totient is φ = 256636240.

The previous prime is 256636223. The next prime is 256636279. The reversal of 256636241 is 142636652.

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., 247149841 + 9486400 = 15721^2 + 3080^2 .

It is a cyclic number.

It is not a de Polignac number, because 256636241 - 2¹⁰ = 256635217 is a prime.

It is a super-2 number, since 2×256636241² = 131724320389220162, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (256636201) 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, 128318120 + 128318121.

It is an arithmetic number, because the mean of its divisors is an integer number (128318121).

Almost surely, 2^256636241 is an apocalyptic number.

It is an amenable number.

256636241 is a deficient number, since it is larger than the sum of its proper divisors (1).

256636241 is an equidigital number, since it uses as much as digits as its factorization.

256636241 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 35.

The square root of 256636241 is about 16019.8701929822. The cubic root of 256636241 is about 635.4860114581.

The spelling of 256636241 in words is "two hundred fifty-six million, six hundred thirty-six thousand, two hundred forty-one".