1811604 has 12 divisors (see below), whose sum is σ = 4227104. Its totient is φ = 603864.

The previous prime is 1811603. The next prime is 1811627. The reversal of 1811604 is 4061181.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1811603) 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, 75472 + ... + 75495.

2^1811604 is an apocalyptic number.

It is an amenable number.

1811604 is an abundant number, since it is smaller than the sum of its proper divisors (2415500).

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

1811604 is a wasteful number, since it uses less digits than its factorization.

1811604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150974 (or 150972 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 1811604 is about 1345.9583946022. The cubic root of 1811604 is about 121.9048797219.

Adding to 1811604 its reverse (4061181), we get a palindrome (5872785).

It can be divided in two parts, 1811 and 604, that added together give a triangular number (2415 = T₆₉).

The spelling of 1811604 in words is "one million, eight hundred eleven thousand, six hundred four".