21336 has 32 divisors (see below), whose sum is σ = 61440. Its totient is φ = 6048.

The previous prime is 21323. The next prime is 21341. The reversal of 21336 is 63312.

21336 = T₆₉ + T₇₀ + ... + T₇₆.

It is a nude number because it is divisible by every one of its digits.

It is a nialpdrome in base 13.

It is a zygodrome in base 13.

It is a congruent number.

It is an unprimeable number.

21336 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105 + ... + 231.

It is an arithmetic number, because the mean of its divisors is an integer number (1920).

2²¹³³⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30720).

21336 is an abundant number, since it is smaller than the sum of its proper divisors (40104).

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

21336 is a wasteful number, since it uses less digits than its factorization.

21336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143 (or 139 counting only the distinct ones).

The product of its digits is 108, while the sum is 15.

The square root of 21336 is about 146.0684770921. The cubic root of 21336 is about 27.7356065280.

Subtracting from 21336 its sum of digits (15), we obtain a triangular number (21321 = T₂₀₆).

Adding to 21336 its reverse (63312), we get a palindrome (84648).

It can be divided in two parts, 21 and 336, that multiplied together give a square (7056 = 84²).

The spelling of 21336 in words is "twenty-one thousand, three hundred thirty-six".