9864821 has 4 divisors (see below), whose sum is σ = 9896652. Its totient is φ = 9832992.

The previous prime is 9864817. The next prime is 9864823. The reversal of 9864821 is 1284689.

9864821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1284689 = 7 ⋅183527.

It can be written as a sum of positive squares in 2 ways, for example, as 470596 + 9394225 = 686^2 + 3065^2 .

It is a cyclic number.

It is not a de Polignac number, because 9864821 - 2² = 9864817 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 (9864823) 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, 15446 + ... + 16071.

It is an arithmetic number, because the mean of its divisors is an integer number (2474163).

Almost surely, 2^9864821 is an apocalyptic number.

It is an amenable number.

9864821 is a deficient number, since it is larger than the sum of its proper divisors (31831).

9864821 is a wasteful number, since it uses less digits than its factorization.

9864821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31830.

The product of its digits is 27648, while the sum is 38.

The square root of 9864821 is about 3140.8312593961. The cubic root of 9864821 is about 214.4682804563.

The spelling of 9864821 in words is "nine million, eight hundred sixty-four thousand, eight hundred twenty-one".