2181604 has 12 divisors (see below), whose sum is σ = 3880828. Its totient is φ = 1072800.

The previous prime is 2181601. The next prime is 2181607. The reversal of 2181604 is 4061812.

It is an interprime number because it is at equal distance from previous prime (2181601) and next prime (2181607).

It can be written as a sum of positive squares in 2 ways, for example, as 624100 + 1557504 = 790^2 + 1248^2 .

It is not an unprimeable number, because it can be changed into a prime (2181601) 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, 4227 + ... + 4714.

2^2181604 is an apocalyptic number.

It is an amenable number.

2181604 is a deficient number, since it is larger than the sum of its proper divisors (1699224).

2181604 is a wasteful number, since it uses less digits than its factorization.

2181604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9006 (or 9004 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 2181604 is about 1477.0253890844. The cubic root of 2181604 is about 129.6956192430.

The spelling of 2181604 in words is "two million, one hundred eighty-one thousand, six hundred four".