9991993840 has 40 divisors (see below), whose sum is σ = 23448521520. Its totient is φ = 3959440896.

The previous prime is 9991993829. The next prime is 9991993841. The reversal of 9991993840 is 483991999.

9991993840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-3 number, since 3×9991993840³ (a number of 31 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9991993841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 575085 + ... + 592204.

It is an arithmetic number, because the mean of its divisors is an integer number (586213038).

Almost surely, 2^9991993840 is an apocalyptic number.

It is an amenable number.

9991993840 is an abundant number, since it is smaller than the sum of its proper divisors (13456527680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9991993840 is a wasteful number, since it uses less digits than its factorization.

9991993840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1167409 (or 1167403 counting only the distinct ones).

The product of its (nonzero) digits is 5668704, while the sum is 61.

The square root of 9991993840 is about 99959.9611844663. The cubic root of 9991993840 is about 2153.8595782287.

The spelling of 9991993840 in words is "nine billion, nine hundred ninety-one million, nine hundred ninety-three thousand, eight hundred forty".