1809216 has 70 divisors (see below), whose sum is σ = 5378450. Its totient is φ = 601344.

The previous prime is 1809211. The next prime is 1809217. The reversal of 1809216 is 6129081.

It can be written as a sum of positive squares in only one way, i.e., 1679616 + 129600 = 1296^2 + 360^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nialpdrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 1809216.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1809211) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 5010 + ... + 5358.

It is an arithmetic number, because the mean of its divisors is an integer number (76835).

2^1809216 is an apocalyptic number.

1809216 is a gapful number since it is divisible by the number (16) 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 1809216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2689225).

1809216 is an abundant number, since it is smaller than the sum of its proper divisors (3569234).

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

1809216 is an equidigital number, since it uses as much as digits as its factorization.

1809216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373 (or 354 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 1809216 is about 1345.0710018434. The cubic root of 1809216 is about 121.8512924300.

It can be divided in two parts, 1809 and 216, that added together give a square (2025 = 45²).

The spelling of 1809216 in words is "one million, eight hundred nine thousand, two hundred sixteen".