1256170542409 has 2 divisors, whose sum is σ = 1256170542410. Its totient is φ = 1256170542408.

The previous prime is 1256170542379. The next prime is 1256170542457. The reversal of 1256170542409 is 9042450716521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 811377585225 + 444792957184 = 900765^2 + 666928^2 .

It is a cyclic number.

It is not a de Polignac number, because 1256170542409 - 2⁹ = 1256170541897 is a prime.

It is a super-2 number, since 2×1256170542409² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1256170542499) 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, 628085271204 + 628085271205.

It is an arithmetic number, because the mean of its divisors is an integer number (628085271205).

Almost surely, 2^{1256170542409} is an apocalyptic number.

It is an amenable number.

1256170542409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256170542409 is an equidigital number, since it uses as much as digits as its factorization.

1256170542409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 604800, while the sum is 46.

The spelling of 1256170542409 in words is "one trillion, two hundred fifty-six billion, one hundred seventy million, five hundred forty-two thousand, four hundred nine".