9991993842 has 64 divisors (see below), whose sum is σ = 22942233600. Its totient is φ = 3220197120.

The previous prime is 9991993841. The next prime is 9991993849. The reversal of 9991993842 is 2483991999.

It is a self number, because there is not a number n which added to its sum of digits gives 9991993842.

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

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2390058 + ... + 2394234.

It is an arithmetic number, because the mean of its divisors is an integer number (358472400).

Almost surely, 2^9991993842 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9991993842, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11471116800).

9991993842 is an abundant number, since it is smaller than the sum of its proper divisors (12950239758).

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

9991993842 is a wasteful number, since it uses less digits than its factorization.

9991993842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5648 (or 5642 counting only the distinct ones).

The product of its digits is 11337408, while the sum is 63.

The square root of 9991993842 is about 99959.9611944703. The cubic root of 9991993842 is about 2153.8595783724.

The spelling of 9991993842 in words is "nine billion, nine hundred ninety-one million, nine hundred ninety-three thousand, eight hundred forty-two".