21326144 has 56 divisors (see below), whose sum is σ = 48816768. Its totient is φ = 9054720.

The previous prime is 21326131. The next prime is 21326161. The reversal of 21326144 is 44162312.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80957 + ... + 81219.

It is an arithmetic number, because the mean of its divisors is an integer number (871728).

Almost surely, 2^21326144 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 21326144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24408384).

21326144 is an abundant number, since it is smaller than the sum of its proper divisors (27490624).

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

21326144 is a wasteful number, since it uses less digits than its factorization.

21326144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463 (or 453 counting only the distinct ones).

The product of its digits is 1152, while the sum is 23.

The square root of 21326144 is about 4618.0238197740. The cubic root of 21326144 is about 277.3133512066.

Adding to 21326144 its reverse (44162312), we get a palindrome (65488456).

The spelling of 21326144 in words is "twenty-one million, three hundred twenty-six thousand, one hundred forty-four".