16566 has 16 divisors (see below), whose sum is σ = 36288. Its totient is φ = 5000.

The previous prime is 16561. The next prime is 16567. The reversal of 16566 is 66561.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60 + ... + 191.

It is an arithmetic number, because the mean of its divisors is an integer number (2268).

2¹⁶⁵⁶⁶ is an apocalyptic number.

16566 is an abundant number, since it is smaller than the sum of its proper divisors (19722).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18144).

16566 is a wasteful number, since it uses less digits than its factorization.

16566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267.

The product of its digits is 1080, while the sum is 24.

The square root of 16566 is about 128.7089740461. The cubic root of 16566 is about 25.4921159787.

It can be divided in two parts, 165 and 66, that added together give a triangular number (231 = T₂₁).

The spelling of 16566 in words is "sixteen thousand, five hundred sixty-six".