1809220 has 24 divisors (see below), whose sum is σ = 4342464. Its totient is φ = 620256.

The previous prime is 1809217. The next prime is 1809221. The reversal of 1809220 is 229081.

It is a junction number, because it is equal to n+sod(n) for n = 1809191 and 1809200.

It is not an unprimeable number, because it can be changed into a prime (1809221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6322 + ... + 6601.

It is an arithmetic number, because the mean of its divisors is an integer number (180936).

2^1809220 is an apocalyptic number.

1809220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1809220 is an abundant number, since it is smaller than the sum of its proper divisors (2533244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1809220 is a wasteful number, since it uses less digits than its factorization.

1809220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12939 (or 12937 counting only the distinct ones).

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

The square root of 1809220 is about 1345.0724887529. The cubic root of 1809220 is about 121.8513822304.

The spelling of 1809220 in words is "one million, eight hundred nine thousand, two hundred twenty".