9987391 has 2 divisors, whose sum is σ = 9987392. Its totient is φ = 9987390.

The previous prime is 9987389. The next prime is 9987403. The reversal of 9987391 is 1937899.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9987391 - 2¹ = 9987389 is a prime.

Together with 9987389, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9987311) 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 as a sum of consecutive naturals, namely, 4993695 + 4993696.

It is an arithmetic number, because the mean of its divisors is an integer number (4993696).

Almost surely, 2^9987391 is an apocalyptic number.

9987391 is a deficient number, since it is larger than the sum of its proper divisors (1).

9987391 is an equidigital number, since it uses as much as digits as its factorization.

9987391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 122472, while the sum is 46.

The square root of 9987391 is about 3160.2833733702. The cubic root of 9987391 is about 215.3528800279.

The spelling of 9987391 in words is "nine million, nine hundred eighty-seven thousand, three hundred ninety-one".