8402821 has 4 divisors (see below), whose sum is σ = 9603232. Its totient is φ = 7202412.

The previous prime is 8402803. The next prime is 8402831. The reversal of 8402821 is 1282048.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 8402821 - 2⁹ = 8402309 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 (8402831) 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, 600195 + ... + 600208.

It is an arithmetic number, because the mean of its divisors is an integer number (2400808).

Almost surely, 2^8402821 is an apocalyptic number.

It is an amenable number.

8402821 is a deficient number, since it is larger than the sum of its proper divisors (1200411).

8402821 is a wasteful number, since it uses less digits than its factorization.

8402821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1200410.

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 8402821 is about 2898.7619771206. The cubic root of 8402821 is about 203.3020248011.

Adding to 8402821 its reverse (1282048), we get a palindrome (9684869).

The spelling of 8402821 in words is "eight million, four hundred two thousand, eight hundred twenty-one".