1809365 has 4 divisors (see below), whose sum is σ = 2171244. Its totient is φ = 1447488.

The previous prime is 1809349. The next prime is 1809373. The reversal of 1809365 is 5639081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5639081 = 7 ⋅805583.

It can be written as a sum of positive squares in 2 ways, for example, as 1100401 + 708964 = 1049^2 + 842^2 .

It is a cyclic number.

It is not a de Polignac number, because 1809365 - 2⁴ = 1809349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 180932 + ... + 180941.

It is an arithmetic number, because the mean of its divisors is an integer number (542811).

2^1809365 is an apocalyptic number.

It is an amenable number.

1809365 is a deficient number, since it is larger than the sum of its proper divisors (361879).

1809365 is an equidigital number, since it uses as much as digits as its factorization.

1809365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361878.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 1809365 is about 1345.1263881138. The cubic root of 1809365 is about 121.8546374045.

The spelling of 1809365 in words is "one million, eight hundred nine thousand, three hundred sixty-five".