9986821 has 12 divisors (see below), whose sum is σ = 11047876. Its totient is φ = 8974080.

The previous prime is 9986813. The next prime is 9986831. The reversal of 9986821 is 1286899.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 2772225 + 7214596 = 1665^2 + 2686^2 .

It is not a de Polignac number, because 9986821 - 2³ = 9986813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9986831) 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, 21625 + ... + 22081.

Almost surely, 2^9986821 is an apocalyptic number.

It is an amenable number.

9986821 is a deficient number, since it is larger than the sum of its proper divisors (1061055).

9986821 is a wasteful number, since it uses less digits than its factorization.

9986821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552 (or 511 counting only the distinct ones).

The product of its digits is 62208, while the sum is 43.

The square root of 9986821 is about 3160.1931902971. The cubic root of 9986821 is about 215.3487830795.

The spelling of 9986821 in words is "nine million, nine hundred eighty-six thousand, eight hundred twenty-one".