1220809 has 4 divisors (see below), whose sum is σ = 1227204. Its totient is φ = 1214416.

The previous prime is 1220803. The next prime is 1220819. The reversal of 1220809 is 9080221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9080221 = 797 ⋅11393.

It can be written as a sum of positive squares in 2 ways, for example, as 921600 + 299209 = 960^2 + 547^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220809 - 2³ = 1220801 is a prime.

It is a super-2 number, since 2×1220809² = 2980749228962, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1220809.

It is not an unprimeable number, because it can be changed into a prime (1220801) 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, 2902 + ... + 3295.

It is an arithmetic number, because the mean of its divisors is an integer number (306801).

2^1220809 is an apocalyptic number.

It is an amenable number.

1220809 is a deficient number, since it is larger than the sum of its proper divisors (6395).

1220809 is an equidigital number, since it uses as much as digits as its factorization.

1220809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6394.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 1220809 is about 1104.9022581206. The cubic root of 1220809 is about 106.8765863905.

The spelling of 1220809 in words is "one million, two hundred twenty thousand, eight hundred nine".