9399991 has 4 divisors (see below), whose sum is σ = 9528832. Its totient is φ = 9271152.

The previous prime is 9399989. The next prime is 9400009. The reversal of 9399991 is 1999939.

9399991 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1999939 = 41 ⋅48779.

It is a cyclic number.

It is not a de Polignac number, because 9399991 - 2¹ = 9399989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9399191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64311 + ... + 64456.

It is an arithmetic number, because the mean of its divisors is an integer number (2382208).

Almost surely, 2^9399991 is an apocalyptic number.

9399991 is a deficient number, since it is larger than the sum of its proper divisors (128841).

9399991 is a wasteful number, since it uses less digits than its factorization.

9399991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128840.

The product of its digits is 177147, while the sum is 49.

The square root of 9399991 is about 3065.9404756127. The cubic root of 9399991 is about 211.0453620941.

The spelling of 9399991 in words is "nine million, three hundred ninety-nine thousand, nine hundred ninety-one".