1808641 has 4 divisors (see below), whose sum is σ = 1813252. Its totient is φ = 1804032.

The previous prime is 1808627. The next prime is 1808669. The reversal of 1808641 is 1468081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1468081 = 661 ⋅2221.

It can be written as a sum of positive squares in 2 ways, for example, as 960400 + 848241 = 980^2 + 921^2 .

It is a cyclic number.

It is not a de Polignac number, because 1808641 - 2¹⁷ = 1677569 is a prime.

It is a Duffinian number.

1808641 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1808041) 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, 1656 + ... + 2521.

It is an arithmetic number, because the mean of its divisors is an integer number (453313).

2^1808641 is an apocalyptic number.

It is an amenable number.

1808641 is a deficient number, since it is larger than the sum of its proper divisors (4611).

1808641 is an equidigital number, since it uses as much as digits as its factorization.

1808641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4610.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 1808641 is about 1344.8572414944. The cubic root of 1808641 is about 121.8383822492.

The spelling of 1808641 in words is "one million, eight hundred eight thousand, six hundred forty-one".