9939 has 4 divisors (see below), whose sum is σ = 13256. Its totient is φ = 6624.

The previous prime is 9931. The next prime is 9941. The reversal of 9939 is 9399.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 9939 - 2³ = 9931 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (9931) 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, 1654 + ... + 1659.

It is an arithmetic number, because the mean of its divisors is an integer number (3314).

2⁹⁹³⁹ is an apocalyptic number.

9939 is a deficient number, since it is larger than the sum of its proper divisors (3317).

9939 is a wasteful number, since it uses less digits than its factorization.

9939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3316.

The product of its digits is 2187, while the sum is 30.

The square root of 9939 is about 99.6945334509. The cubic root of 9939 is about 21.5004506846.

The spelling of 9939 in words is "nine thousand, nine hundred thirty-nine".