9991173 has 4 divisors (see below), whose sum is σ = 13321568. Its totient is φ = 6660780.

The previous prime is 9991159. The next prime is 9991183. The reversal of 9991173 is 3711999.

9991173 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 a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 9991173 - 2⁵ = 9991141 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 (9991123) 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, 1665193 + ... + 1665198.

It is an arithmetic number, because the mean of its divisors is an integer number (3330392).

Almost surely, 2^9991173 is an apocalyptic number.

It is an amenable number.

9991173 is a deficient number, since it is larger than the sum of its proper divisors (3330395).

9991173 is a wasteful number, since it uses less digits than its factorization.

9991173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3330394.

The product of its digits is 15309, while the sum is 39.

The square root of 9991173 is about 3160.8816807973. The cubic root of 9991173 is about 215.3800596924.

The spelling of 9991173 in words is "nine million, nine hundred ninety-one thousand, one hundred seventy-three".