16639 has 4 divisors (see below), whose sum is σ = 19024. Its totient is φ = 14256.

The previous prime is 16633. The next prime is 16649. The reversal of 16639 is 93661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93661 = 229 ⋅409.

It is a cyclic number.

It is not a de Polignac number, because 16639 - 2³ = 16631 is a prime.

It is a Kynea number, being equal to (2⁷ + 1)² - 2.

It is a Duffinian number.

16639 is a lucky number.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16631) 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, 1182 + ... + 1195.

It is an arithmetic number, because the mean of its divisors is an integer number (4756).

2¹⁶⁶³⁹ is an apocalyptic number.

16639 is a deficient number, since it is larger than the sum of its proper divisors (2385).

16639 is an equidigital number, since it uses as much as digits as its factorization.

16639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2384.

The product of its digits is 972, while the sum is 25.

The square root of 16639 is about 128.9922478291. The cubic root of 16639 is about 25.5295057666.

The spelling of 16639 in words is "sixteen thousand, six hundred thirty-nine".