21268144 has 40 divisors (see below), whose sum is σ = 44411840. Its totient is φ = 9834048.

The previous prime is 21268129. The next prime is 21268147. The reversal of 21268144 is 44186212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21268147) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12259 + ... + 13885.

It is an arithmetic number, because the mean of its divisors is an integer number (1110296).

Almost surely, 2^21268144 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 21268144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22205920).

21268144 is an abundant number, since it is smaller than the sum of its proper divisors (23143696).

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

21268144 is a wasteful number, since it uses less digits than its factorization.

21268144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1697 (or 1691 counting only the distinct ones).

The product of its digits is 3072, while the sum is 28.

The square root of 21268144 is about 4611.7398018535. The cubic root of 21268144 is about 277.0617230073.

It can be divided in two parts, 21268 and 144, that added together give a palindrome (21412).

The spelling of 21268144 in words is "twenty-one million, two hundred sixty-eight thousand, one hundred forty-four".