7220809 has 4 divisors (see below), whose sum is σ = 7416004. Its totient is φ = 7025616.

The previous prime is 7220803. The next prime is 7220821. The reversal of 7220809 is 9080227.

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 6864400 + 356409 = 2620^2 + 597^2 .

It is a cyclic number.

It is not a de Polignac number, because 7220809 - 2¹⁷ = 7089737 is a prime.

It is a super-2 number, since 2×7220809² = 104280165228962, which contains 22 as substring.

It is a Duffinian number.

7220809 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (7220803) 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, 97542 + ... + 97615.

It is an arithmetic number, because the mean of its divisors is an integer number (1854001).

Almost surely, 2^7220809 is an apocalyptic number.

It is an amenable number.

7220809 is a deficient number, since it is larger than the sum of its proper divisors (195195).

7220809 is a wasteful number, since it uses less digits than its factorization.

7220809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195194.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 7220809 is about 2687.1563036042. The cubic root of 7220809 is about 193.2837245553.

The spelling of 7220809 in words is "seven million, two hundred twenty thousand, eight hundred nine".