9991924 has 24 divisors (see below), whose sum is σ = 18106088. Its totient is φ = 4821120.

The previous prime is 9991879. The next prime is 9991939. The reversal of 9991924 is 4291999.

It can be written as a sum of positive squares in 4 ways, for example, as 883600 + 9108324 = 940^2 + 3018^2 .

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 26602 + ... + 26974.

Almost surely, 2^9991924 is an apocalyptic number.

It is an amenable number.

9991924 is a deficient number, since it is larger than the sum of its proper divisors (8114164).

9991924 is a wasteful number, since it uses less digits than its factorization.

9991924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 595 (or 593 counting only the distinct ones).

The product of its digits is 52488, while the sum is 43.

The square root of 9991924 is about 3161.0004745333. Note that the first 3 decimals coincide. The cubic root of 9991924 is about 215.3854560014.

The spelling of 9991924 in words is "nine million, nine hundred ninety-one thousand, nine hundred twenty-four".