9991438903 has 2 divisors, whose sum is σ = 9991438904. Its totient is φ = 9991438902.

The previous prime is 9991438889. The next prime is 9991438921. The reversal of 9991438903 is 3098341999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9991438903 - 2¹⁷ = 9991307831 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9991438103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995719451 + 4995719452.

It is an arithmetic number, because the mean of its divisors is an integer number (4995719452).

Almost surely, 2^9991438903 is an apocalyptic number.

9991438903 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991438903 is an equidigital number, since it uses as much as digits as its factorization.

9991438903 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1889568, while the sum is 55.

The square root of 9991438903 is about 99957.1853495285. The cubic root of 9991438903 is about 2153.8197036878.

The spelling of 9991438903 in words is "nine billion, nine hundred ninety-one million, four hundred thirty-eight thousand, nine hundred three".