9993991 has 8 divisors (see below), whose sum is σ = 11655200. Its totient is φ = 8565984.

The previous prime is 9993989. The next prime is 9994001. The reversal of 9993991 is 1993999.

9993991 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 9993991 - 2¹ = 9993989 is a prime.

It is a super-2 number, since 2×9993991² = 199759712216162, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9993901) 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 7 ways as a sum of consecutive naturals, for example, 14226 + ... + 14911.

It is an arithmetic number, because the mean of its divisors is an integer number (1456900).

Almost surely, 2^9993991 is an apocalyptic number.

9993991 is a deficient number, since it is larger than the sum of its proper divisors (1661209).

9993991 is an equidigital number, since it uses as much as digits as its factorization.

9993991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29158 (or 29144 counting only the distinct ones).

The product of its digits is 177147, while the sum is 49.

The square root of 9993991 is about 3161.3274110728. The cubic root of 9993991 is about 215.4003070298.

The spelling of 9993991 in words is "nine million, nine hundred ninety-three thousand, nine hundred ninety-one".