9810991 has 2 divisors, whose sum is σ = 9810992. Its totient is φ = 9810990.

The previous prime is 9810979. The next prime is 9811001. The reversal of 9810991 is 1990189.

It is a strong prime.

It is an emirp because it is prime and its reverse (1990189) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9810991 - 2⁷ = 9810863 is a prime.

9810991 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 9810991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9810901) 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, 4905495 + 4905496.

It is an arithmetic number, because the mean of its divisors is an integer number (4905496).

Almost surely, 2^9810991 is an apocalyptic number.

9810991 is a deficient number, since it is larger than the sum of its proper divisors (1).

9810991 is an equidigital number, since it uses as much as digits as its factorization.

9810991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 37.

The square root of 9810991 is about 3132.2501496528. The cubic root of 9810991 is about 214.0774678045.

It can be divided in two parts, 9810 and 991, that added together give a palindrome (10801).

The spelling of 9810991 in words is "nine million, eight hundred ten thousand, nine hundred ninety-one".