21321244 has 24 divisors (see below), whose sum is σ = 42812000. Its totient is φ = 9101376.

The previous prime is 21321217. The next prime is 21321263. The reversal of 21321244 is 44212312.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6382 + ... + 9130.

Almost surely, 2^21321244 is an apocalyptic number.

It is an amenable number.

21321244 is an abundant number, since it is smaller than the sum of its proper divisors (21490756).

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

21321244 is a wasteful number, since it uses less digits than its factorization.

21321244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3037 (or 3035 counting only the distinct ones).

The product of its digits is 384, while the sum is 19.

The square root of 21321244 is about 4617.4932593345. The cubic root of 21321244 is about 277.2921106187.

Adding to 21321244 its reverse (44212312), we get a palindrome (65533556).

The spelling of 21321244 in words is "twenty-one million, three hundred twenty-one thousand, two hundred forty-four".