16663 has 4 divisors (see below), whose sum is σ = 17560. Its totient is φ = 15768.

The previous prime is 16661. The next prime is 16673. The reversal of 16663 is 36661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 36661 = 61 ⋅601.

It is a cyclic number.

It is not a de Polignac number, because 16663 - 2¹ = 16661 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11 and base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16661) 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, 420 + ... + 457.

It is an arithmetic number, because the mean of its divisors is an integer number (4390).

2¹⁶⁶⁶³ is an apocalyptic number.

16663 is a deficient number, since it is larger than the sum of its proper divisors (897).

16663 is an equidigital number, since it uses as much as digits as its factorization.

16663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 896.

The product of its digits is 648, while the sum is 22.

The square root of 16663 is about 129.0852431535. The cubic root of 16663 is about 25.5417744082.

Subtracting from 16663 its sum of digits (22), we obtain a square (16641 = 129²).

The spelling of 16663 in words is "sixteen thousand, six hundred sixty-three".