8204721 has 16 divisors (see below), whose sum is σ = 13046784. Its totient is φ = 4484304.

The previous prime is 8204719. The next prime is 8204737. The reversal of 8204721 is 1274028.

It is not a de Polignac number, because 8204721 - 2¹ = 8204719 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 8204691 and 8204700.

It is not an unprimeable number, because it can be changed into a prime (8204741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8011 + ... + 8976.

It is an arithmetic number, because the mean of its divisors is an integer number (815424).

Almost surely, 2^8204721 is an apocalyptic number.

It is an amenable number.

8204721 is a deficient number, since it is larger than the sum of its proper divisors (4842063).

8204721 is a wasteful number, since it uses less digits than its factorization.

8204721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17020.

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 8204721 is about 2864.3884163989. The cubic root of 8204721 is about 201.6916594331.

Adding to 8204721 its reverse (1274028), we get a palindrome (9478749).

The spelling of 8204721 in words is "eight million, two hundred four thousand, seven hundred twenty-one".