2091918128849 has 2 divisors, whose sum is σ = 2091918128850. Its totient is φ = 2091918128848.

The previous prime is 2091918128821. The next prime is 2091918128887. The reversal of 2091918128849 is 9488218191902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1993913443600 + 98004685249 = 1412060^2 + 313057^2 .

It is a cyclic number.

It is not a de Polignac number, because 2091918128849 - 2²⁰ = 2091917080273 is a prime.

It is a super-2 number, since 2×2091918128849² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2091918128791 and 2091918128800.

It is not a weakly prime, because it can be changed into another prime (2091918125849) 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, 1045959064424 + 1045959064425.

It is an arithmetic number, because the mean of its divisors is an integer number (1045959064425).

Almost surely, 2^{2091918128849} is an apocalyptic number.

It is an amenable number.

2091918128849 is a deficient number, since it is larger than the sum of its proper divisors (1).

2091918128849 is an equidigital number, since it uses as much as digits as its factorization.

2091918128849 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5971968, while the sum is 62.

The spelling of 2091918128849 in words is "two trillion, ninety-one billion, nine hundred eighteen million, one hundred twenty-eight thousand, eight hundred forty-nine".