19856 has 20 divisors (see below), whose sum is σ = 41292. Its totient is φ = 9216.

The previous prime is 19853. The next prime is 19861. The reversal of 19856 is 65891.

19856 = T₁₈ + T₁₉ + ... + T₄₉.

It can be written as a sum of positive squares in 2 ways, for example, as 13456 + 6400 = 116^2 + 80^2 .

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 19856.

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, 236 + ... + 308.

2¹⁹⁸⁵⁶ is an apocalyptic number.

19856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20646).

19856 is an abundant number, since it is smaller than the sum of its proper divisors (21436).

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

19856 is a wasteful number, since it uses less digits than its factorization.

19856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 92 counting only the distinct ones).

The product of its digits is 2160, while the sum is 29.

The square root of 19856 is about 140.9113196305. The cubic root of 19856 is about 27.0788731643.

It can be divided in two parts, 1985 and 6, that added together give a palindrome (1991).

The spelling of 19856 in words is "nineteen thousand, eight hundred fifty-six".