1904405 has 4 divisors (see below), whose sum is σ = 2285292. Its totient is φ = 1523520.

The previous prime is 1904311. The next prime is 1904407. The reversal of 1904405 is 5044091.

Added to its reverse (5044091) it gives a square (6948496 = 2636²).

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1249924 + 654481 = 1118^2 + 809^2 .

It is not a de Polignac number, because 1904405 - 2¹⁰ = 1903381 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1904407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190436 + ... + 190445.

It is an arithmetic number, because the mean of its divisors is an integer number (571323).

2^1904405 is an apocalyptic number.

It is an amenable number.

1904405 is a deficient number, since it is larger than the sum of its proper divisors (380887).

1904405 is an equidigital number, since it uses as much as digits as its factorization.

1904405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380886.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 1904405 is about 1380.0018115930. The cubic root of 1904405 is about 123.9518760534.

Adding to 1904405 its reverse (5044091), we get a palindrome (6948496).

The spelling of 1904405 in words is "one million, nine hundred four thousand, four hundred five".