9988691 has 2 divisors, whose sum is σ = 9988692. Its totient is φ = 9988690.

The previous prime is 9988687. The next prime is 9988697. The reversal of 9988691 is 1968899.

9988691 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is an emirp because it is prime and its reverse (1968899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9988691 - 2² = 9988687 is a prime.

It is not a weakly prime, because it can be changed into another prime (9988697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4994345 + 4994346.

It is an arithmetic number, because the mean of its divisors is an integer number (4994346).

Almost surely, 2^9988691 is an apocalyptic number.

9988691 is a deficient number, since it is larger than the sum of its proper divisors (1).

9988691 is an equidigital number, since it uses as much as digits as its factorization.

9988691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 50.

The square root of 9988691 is about 3160.4890444360. The cubic root of 9988691 is about 215.3622233622.

The spelling of 9988691 in words is "nine million, nine hundred eighty-eight thousand, six hundred ninety-one".