19859 has 4 divisors (see below), whose sum is σ = 22704. Its totient is φ = 17016.

The previous prime is 19853. The next prime is 19861. The reversal of 19859 is 95891.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19859 - 2⁴ = 19843 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19853) 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, 1412 + ... + 1425.

It is an arithmetic number, because the mean of its divisors is an integer number (5676).

2¹⁹⁸⁵⁹ is an apocalyptic number.

19859 is a deficient number, since it is larger than the sum of its proper divisors (2845).

19859 is an equidigital number, since it uses as much as digits as its factorization.

19859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2844.

The product of its digits is 3240, while the sum is 32.

The square root of 19859 is about 140.9219642213. The cubic root of 19859 is about 27.0802368583.

Adding to 19859 its sum of digits (32), we get a palindrome (19891).

It can be divided in two parts, 19 and 859, that added together give a palindrome (878).

The spelling of 19859 in words is "nineteen thousand, eight hundred fifty-nine".