8220809 has 4 divisors (see below), whose sum is σ = 8704404. Its totient is φ = 7737216.

The previous prime is 8220803. The next prime is 8220851. The reversal of 8220809 is 9080228.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5895184 + 2325625 = 2428^2 + 1525^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8220809 is a prime.

It is a super-2 number, since 2×8220809² = 135163401228962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8220803) 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, 241772 + ... + 241805.

It is an arithmetic number, because the mean of its divisors is an integer number (2176101).

Almost surely, 2^8220809 is an apocalyptic number.

It is an amenable number.

8220809 is a deficient number, since it is larger than the sum of its proper divisors (483595).

8220809 is a wasteful number, since it uses less digits than its factorization.

8220809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 483594.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 8220809 is about 2867.1953194716. The cubic root of 8220809 is about 201.8234005323.

The spelling of 8220809 in words is "eight million, two hundred twenty thousand, eight hundred nine".