21296 has 20 divisors (see below), whose sum is σ = 45384. Its totient is φ = 9680.

The previous prime is 21283. The next prime is 21313. The reversal of 21296 is 69212.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is an alternating number because its digits alternate between even and odd.

It is a nialpdrome in base 16.

It is an unprimeable number.

21296 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1931 + ... + 1941.

2²¹²⁹⁶ 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 21296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22692).

21296 is an abundant number, since it is smaller than the sum of its proper divisors (24088).

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

21296 is an equidigital number, since it uses as much as digits as its factorization.

21296 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41 (or 13 counting only the distinct ones).

The product of its digits is 216, while the sum is 20.

The square root of 21296 is about 145.9314907756. The cubic root of 21296 is about 27.7182630977.

Adding to 21296 its sum of digits (20), we get a square (21316 = 146²).

Adding to 21296 its product of digits (216), we get a palindrome (21512).

It can be divided in two parts, 21 and 296, that multiplied together give a triangular number (6216 = T₁₁₁).

The spelling of 21296 in words is "twenty-one thousand, two hundred ninety-six".