21444072 has 96 divisors (see below), whose sum is σ = 61663680. Its totient is φ = 6190080.

The previous prime is 21444067. The next prime is 21444083. The reversal of 21444072 is 27044412.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 68797 + ... + 69107.

It is an arithmetic number, because the mean of its divisors is an integer number (642330).

Almost surely, 2^21444072 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 21444072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30831840).

21444072 is an abundant number, since it is smaller than the sum of its proper divisors (40219608).

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

21444072 is a wasteful number, since it uses less digits than its factorization.

21444072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363 (or 346 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 24.

The square root of 21444072 is about 4630.7744492687. The cubic root of 21444072 is about 277.8235686763.

Adding to 21444072 its reverse (27044412), we get a palindrome (48488484).

It can be divided in two parts, 2144 and 4072, that added together give a triangular number (6216 = T₁₁₁).

The spelling of 21444072 in words is "twenty-one million, four hundred forty-four thousand, seventy-two".