9933991 has 4 divisors (see below), whose sum is σ = 9945232. Its totient is φ = 9922752.

The previous prime is 9933983. The next prime is 9933997. The reversal of 9933991 is 1993399.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1993399 = 139 ⋅14341.

It is a cyclic number.

It is not a de Polignac number, because 9933991 - 2³ = 9933983 is a prime.

It is a Duffinian number.

9933991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9933997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4170 + ... + 6103.

It is an arithmetic number, because the mean of its divisors is an integer number (2486308).

Almost surely, 2^9933991 is an apocalyptic number.

9933991 is a deficient number, since it is larger than the sum of its proper divisors (11241).

9933991 is a wasteful number, since it uses less digits than its factorization.

9933991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11240.

The product of its digits is 59049, while the sum is 43.

The square root of 9933991 is about 3151.8234404865. The cubic root of 9933991 is about 214.9683818657.

The spelling of 9933991 in words is "nine million, nine hundred thirty-three thousand, nine hundred ninety-one".