1840409 has 4 divisors (see below), whose sum is σ = 1843380. Its totient is φ = 1837440.

The previous prime is 1840393. The next prime is 1840429. The reversal of 1840409 is 9040481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9040481 = 17 ⋅531793.

It can be written as a sum of positive squares in 2 ways, for example, as 994009 + 846400 = 997^2 + 920^2 .

It is a cyclic number.

It is not a de Polignac number, because 1840409 - 2⁴ = 1840393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1840429) 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, 164 + ... + 1925.

It is an arithmetic number, because the mean of its divisors is an integer number (460845).

2^1840409 is an apocalyptic number.

It is an amenable number.

1840409 is a deficient number, since it is larger than the sum of its proper divisors (2971).

1840409 is an equidigital number, since it uses as much as digits as its factorization.

1840409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2970.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 1840409 is about 1356.6167476484. The cubic root of 1840409 is about 122.5475922254.

The spelling of 1840409 in words is "one million, eight hundred forty thousand, four hundred nine".