9818991 has 48 divisors (see below), whose sum is σ = 18403840. Its totient is φ = 4898880.

The previous prime is 9818969. The next prime is 9819031. The reversal of 9818991 is 1998189.

It is not a de Polignac number, because 9818991 - 2⁵ = 9818959 is a prime.

9818991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9818191) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 15246 + ... + 15876.

Almost surely, 2^9818991 is an apocalyptic number.

9818991 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

9818991 is a deficient number, since it is larger than the sum of its proper divisors (8584849).

9818991 is a wasteful number, since it uses less digits than its factorization.

9818991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 676 (or 673 counting only the distinct ones).

The product of its digits is 46656, while the sum is 45.

The square root of 9818991 is about 3133.5269266435. The cubic root of 9818991 is about 214.1356391097.

The spelling of 9818991 in words is "nine million, eight hundred eighteen thousand, nine hundred ninety-one".