21244 has 12 divisors (see below), whose sum is σ = 38304. Its totient is φ = 10304.

The previous prime is 21227. The next prime is 21247. The reversal of 21244 is 44212.

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

21244 is an undulating number in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21247) 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, 132 + ... + 244.

It is an arithmetic number, because the mean of its divisors is an integer number (3192).

2²¹²⁴⁴ is an apocalyptic number.

It is an amenable number.

21244 is a deficient number, since it is larger than the sum of its proper divisors (17060).

21244 is a wasteful number, since it uses less digits than its factorization.

21244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164 (or 162 counting only the distinct ones).

The product of its digits is 64, while the sum is 13.

The square root of 21244 is about 145.7532160880. The cubic root of 21244 is about 27.6956841404.

Adding to 21244 its reverse (44212), we get a palindrome (65456).

It can be divided in two parts, 212 and 44, that added together give a 8-th power (256 = 2⁸).

The spelling of 21244 in words is "twenty-one thousand, two hundred forty-four", and thus it is an iban number.