166404 has 36 divisors (see below), whose sum is σ = 453264. Its totient is φ = 47376.

The previous prime is 166403. The next prime is 166409. The reversal of 166404 is 404661.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a plaindrome in base 15.

It is a nialpdrome in base 6.

It is not an unprimeable number, because it can be changed into a prime (166403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 447 + ... + 729.

2¹⁶⁶⁴⁰⁴ is an apocalyptic number.

166404 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 166404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (226632).

166404 is an abundant number, since it is smaller than the sum of its proper divisors (286860).

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

166404 is a wasteful number, since it uses less digits than its factorization.

166404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304 (or 295 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 166404 is about 407.9264639613. The cubic root of 166404 is about 55.0031954066.

The spelling of 166404 in words is "one hundred sixty-six thousand, four hundred four".