9991993849 has 2 divisors, whose sum is σ = 9991993850. Its totient is φ = 9991993848.

The previous prime is 9991993841. The next prime is 9991993853. The reversal of 9991993849 is 9483991999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9323254249 + 668739600 = 96557^2 + 25860^2 .

It is a cyclic number.

It is not a de Polignac number, because 9991993849 - 2³ = 9991993841 is a prime.

It is not a weakly prime, because it can be changed into another prime (9991993841) 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, 4995996924 + 4995996925.

It is an arithmetic number, because the mean of its divisors is an integer number (4995996925).

Almost surely, 2^9991993849 is an apocalyptic number.

It is an amenable number.

9991993849 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991993849 is an equidigital number, since it uses as much as digits as its factorization.

9991993849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51018336, while the sum is 70.

The square root of 9991993849 is about 99959.9612294843. The cubic root of 9991993849 is about 2153.8595788754.

The spelling of 9991993849 in words is "nine billion, nine hundred ninety-one million, nine hundred ninety-three thousand, eight hundred forty-nine".