21052144 has 40 divisors (see below), whose sum is σ = 42966000. Its totient is φ = 9977856.

The previous prime is 21052127. The next prime is 21052159. The reversal of 21052144 is 44125012.

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, 26992 + ... + 27760.

It is an arithmetic number, because the mean of its divisors is an integer number (1074150).

Almost surely, 2^21052144 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 21052144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21483000).

21052144 is an abundant number, since it is smaller than the sum of its proper divisors (21913856).

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

21052144 is a wasteful number, since it uses less digits than its factorization.

21052144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 865 (or 859 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21052144 is about 4588.2615444196. The cubic root of 21052144 is about 276.1205802329.

Adding to 21052144 its reverse (44125012), we get a palindrome (65177156).

The spelling of 21052144 in words is "twenty-one million, fifty-two thousand, one hundred forty-four".