19669 has 8 divisors (see below), whose sum is σ = 22680. Its totient is φ = 16896.

The previous prime is 19661. The next prime is 19681. The reversal of 19669 is 96691.

It can be written as a sum of positive squares in 4 ways, for example, as 625 + 19044 = 25^2 + 138^2 .

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

It is a 5-Lehmer number, since φ(19669) divides (19669-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 19669 - 2³ = 19661 is a prime.

It is a super-2 number, since 2×19669² = 773739122, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 7.

It is a nialpdrome in base 3.

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 19669.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19661) 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, 177 + ... + 265.

It is an arithmetic number, because the mean of its divisors is an integer number (2835).

It is the magic constant of a 34 × 34 magic square.

2¹⁹⁶⁶⁹ is an apocalyptic number.

19669 is the 89-th heptagonal number.

It is an amenable number.

19669 is a deficient number, since it is larger than the sum of its proper divisors (3011).

19669 is a wasteful number, since it uses less digits than its factorization.

19669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119.

The product of its digits is 2916, while the sum is 31.

The square root of 19669 is about 140.2462120701. The cubic root of 19669 is about 26.9935970185.

The spelling of 19669 in words is "nineteen thousand, six hundred sixty-nine".