9827991 has 12 divisors (see below), whose sum is σ = 14246232. Its totient is φ = 6528816.

The previous prime is 9827981. The next prime is 9827999. The reversal of 9827991 is 1997289.

It is not a de Polignac number, because 9827991 - 2⁶ = 9827927 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9827999) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 985 + ... + 4541.

It is an arithmetic number, because the mean of its divisors is an integer number (1187186).

Almost surely, 2^9827991 is an apocalyptic number.

9827991 is a deficient number, since it is larger than the sum of its proper divisors (4418241).

9827991 is a wasteful number, since it uses less digits than its factorization.

9827991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3870 (or 3867 counting only the distinct ones).

The product of its digits is 81648, while the sum is 45.

The square root of 9827991 is about 3134.9626792037. The cubic root of 9827991 is about 214.2010440727.

The spelling of 9827991 in words is "nine million, eight hundred twenty-seven thousand, nine hundred ninety-one".