1809666 has 12 divisors (see below), whose sum is σ = 3920982. Its totient is φ = 603216.

The previous prime is 1809631. The next prime is 1809671. The reversal of 1809666 is 6669081.

It can be written as a sum of positive squares in only one way, i.e., 1625625 + 184041 = 1275^2 + 429^2 .

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 1809666.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 50251 + ... + 50286.

2^1809666 is an apocalyptic number.

1809666 is an abundant number, since it is smaller than the sum of its proper divisors (2111316).

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

1809666 is a wasteful number, since it uses less digits than its factorization.

1809666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100545 (or 100542 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 1809666 is about 1345.2382688580. The cubic root of 1809666 is about 121.8613941419.

The spelling of 1809666 in words is "one million, eight hundred nine thousand, six hundred sixty-six".