9681821 has 4 divisors (see below), whose sum is σ = 9707100. Its totient is φ = 9656544.

The previous prime is 9681809. The next prime is 9681829. The reversal of 9681821 is 1281869.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1281869 = 227 ⋅5647.

It can be written as a sum of positive squares in 2 ways, for example, as 765625 + 8916196 = 875^2 + 2986^2 .

It is a cyclic number.

It is not a de Polignac number, because 9681821 - 2⁶ = 9681757 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 (9681829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12056 + ... + 12833.

It is an arithmetic number, because the mean of its divisors is an integer number (2426775).

Almost surely, 2^9681821 is an apocalyptic number.

It is an amenable number.

9681821 is a deficient number, since it is larger than the sum of its proper divisors (25279).

9681821 is a wasteful number, since it uses less digits than its factorization.

9681821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25278.

The product of its digits is 6912, while the sum is 35.

The square root of 9681821 is about 3111.5624692427. The cubic root of 9681821 is about 213.1338105765.

The spelling of 9681821 in words is "nine million, six hundred eighty-one thousand, eight hundred twenty-one".