1256847217 has 2 divisors, whose sum is σ = 1256847218. Its totient is φ = 1256847216.

The previous prime is 1256847209. The next prime is 1256847227. The reversal of 1256847217 is 7127486521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1003368976 + 253478241 = 31676^2 + 15921^2 .

It is a cyclic number.

It is not a de Polignac number, because 1256847217 - 2³ = 1256847209 is a prime.

It is not a weakly prime, because it can be changed into another prime (1256847227) 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, 628423608 + 628423609.

It is an arithmetic number, because the mean of its divisors is an integer number (628423609).

Almost surely, 2^1256847217 is an apocalyptic number.

It is an amenable number.

1256847217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256847217 is an equidigital number, since it uses as much as digits as its factorization.

1256847217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 188160, while the sum is 43.

The square root of 1256847217 is about 35452.0410836950. The cubic root of 1256847217 is about 1079.1806820406.

The spelling of 1256847217 in words is "one billion, two hundred fifty-six million, eight hundred forty-seven thousand, two hundred seventeen".