1809920 has 80 divisors (see below), whose sum is σ = 5008608. Its totient is φ = 614400.

The previous prime is 1809917. The next prime is 1809937. The reversal of 1809920 is 299081.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17870 + ... + 17970.

2^1809920 is an apocalyptic number.

1809920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1809920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2504304).

1809920 is an abundant number, since it is smaller than the sum of its proper divisors (3198688).

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

1809920 is an equidigital number, since it uses as much as digits as its factorization.

1809920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 1809920 is about 1345.3326726130. The cubic root of 1809920 is about 121.8670952576.

The spelling of 1809920 in words is "one million, eight hundred nine thousand, nine hundred twenty".