9991438103 has 2 divisors, whose sum is σ = 9991438104. Its totient is φ = 9991438102.

The previous prime is 9991438031. The next prime is 9991438139. The reversal of 9991438103 is 3018341999.

Together with previous prime (9991438031) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 9991438103 - 2¹⁸ = 9991175959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9991438903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995719051 + 4995719052.

It is an arithmetic number, because the mean of its divisors is an integer number (4995719052).

Almost surely, 2^9991438103 is an apocalyptic number.

9991438103 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991438103 is an equidigital number, since it uses as much as digits as its factorization.

9991438103 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 209952, while the sum is 47.

The square root of 9991438103 is about 99957.1813478151. The cubic root of 9991438103 is about 2153.8196462034.

The spelling of 9991438103 in words is "nine billion, nine hundred ninety-one million, four hundred thirty-eight thousand, one hundred three".