9985891 has 2 divisors, whose sum is σ = 9985892. Its totient is φ = 9985890.

The previous prime is 9985879. The next prime is 9985901. The reversal of 9985891 is 1985899.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 9985891 - 2⁷ = 9985763 is a prime.

9985891 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (9985091) 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, 4992945 + 4992946.

It is an arithmetic number, because the mean of its divisors is an integer number (4992946).

Almost surely, 2^9985891 is an apocalyptic number.

9985891 is a deficient number, since it is larger than the sum of its proper divisors (1).

9985891 is an equidigital number, since it uses as much as digits as its factorization.

9985891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 233280, while the sum is 49.

The square root of 9985891 is about 3160.0460439683. The cubic root of 9985891 is about 215.3420982501.

It can be divided in two parts, 998 and 5891, that added together give a square (6889 = 83²).

The spelling of 9985891 in words is "nine million, nine hundred eighty-five thousand, eight hundred ninety-one".