1256618017 has 2 divisors, whose sum is σ = 1256618018. Its totient is φ = 1256618016.

The previous prime is 1256617981. The next prime is 1256618023. The reversal of 1256618017 is 7108166521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1256064481 + 553536 = 35441^2 + 744^2 .

It is an emirp because it is prime and its reverse (7108166521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1256618017 - 2⁷ = 1256617889 is a prime.

It is not a weakly prime, because it can be changed into another prime (1256618047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628309008 + 628309009.

It is an arithmetic number, because the mean of its divisors is an integer number (628309009).

Almost surely, 2^1256618017 is an apocalyptic number.

It is an amenable number.

1256618017 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256618017 is an equidigital number, since it uses as much as digits as its factorization.

1256618017 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 37.

The square root of 1256618017 is about 35448.8084002834. The cubic root of 1256618017 is about 1079.1150778722.

The spelling of 1256618017 in words is "one billion, two hundred fifty-six million, six hundred eighteen thousand, seventeen".