1591843509649 has 2 divisors, whose sum is σ = 1591843509650. Its totient is φ = 1591843509648.

The previous prime is 1591843509637. The next prime is 1591843509677. The reversal of 1591843509649 is 9469053481951.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 860382394624 + 731461115025 = 927568^2 + 855255^2 .

It is a cyclic number.

It is not a de Polignac number, because 1591843509649 - 2¹⁹ = 1591842985361 is a prime.

It is a super-2 number, since 2×1591843509649² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1591843500649) 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, 795921754824 + 795921754825.

It is an arithmetic number, because the mean of its divisors is an integer number (795921754825).

Almost surely, 2^{1591843509649} is an apocalyptic number.

It is an amenable number.

1591843509649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1591843509649 is an equidigital number, since it uses as much as digits as its factorization.

1591843509649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41990400, while the sum is 64.

The spelling of 1591843509649 in words is "one trillion, five hundred ninety-one billion, eight hundred forty-three million, five hundred nine thousand, six hundred forty-nine".