9999939826991 has 2 divisors, whose sum is σ = 9999939826992. Its totient is φ = 9999939826990.

The previous prime is 9999939826969. The next prime is 9999939827041. The reversal of 9999939826991 is 1996289399999.

9999939826991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is an emirp because it is prime and its reverse (1996289399999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9999939826991 - 2¹⁴ = 9999939810607 is a prime.

It is a super-2 number, since 2×9999939826991² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 9999939826991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9999939826931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4999969913495 + 4999969913496.

It is an arithmetic number, because the mean of its divisors is an integer number (4999969913496).

Almost surely, 2^{9999939826991} is an apocalyptic number.

9999939826991 is a deficient number, since it is larger than the sum of its proper divisors (1).

9999939826991 is an equidigital number, since it uses as much as digits as its factorization.

9999939826991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12397455648, while the sum is 92.

The spelling of 9999939826991 in words is "nine trillion, nine hundred ninety-nine billion, nine hundred thirty-nine million, eight hundred twenty-six thousand, nine hundred ninety-one".