166638 has 8 divisors (see below), whose sum is σ = 333288. Its totient is φ = 55544.

The previous prime is 166631. The next prime is 166643. The reversal of 166638 is 836661.

It is a sphenic number, since it is the product of 3 distinct primes.

166638 is an admirable number.

It is a plaindrome in base 16.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 166638.

It is not an unprimeable number, because it can be changed into a prime (166631) 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, 13881 + ... + 13892.

It is an arithmetic number, because the mean of its divisors is an integer number (41661).

2¹⁶⁶⁶³⁸ is an apocalyptic number.

166638 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

166638 is a wasteful number, since it uses less digits than its factorization.

166638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27778.

The product of its digits is 5184, while the sum is 30.

The square root of 166638 is about 408.2131796011. The cubic root of 166638 is about 55.0289654591.

The spelling of 166638 in words is "one hundred sixty-six thousand, six hundred thirty-eight".