21324312 has 96 divisors (see below), whose sum is σ = 61401600. Its totient is φ = 6671808.

The previous prime is 21324301. The next prime is 21324313. The reversal of 21324312 is 21342312.

It is a Harshad number since it is a multiple of its sum of digits (18).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21324313) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 130743 + ... + 130905.

It is an arithmetic number, because the mean of its divisors is an integer number (639600).

Almost surely, 2^21324312 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 21324312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30700800).

21324312 is an abundant number, since it is smaller than the sum of its proper divisors (40077288).

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

21324312 is a wasteful number, since it uses less digits than its factorization.

21324312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277 (or 270 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21324312 is about 4617.8254622712. The cubic root of 21324312 is about 277.3054102085.

Adding to 21324312 its reverse (21342312), we get a palindrome (42666624).

The spelling of 21324312 in words is "twenty-one million, three hundred twenty-four thousand, three hundred twelve".