21434144 has 72 divisors (see below), whose sum is σ = 47294604. Its totient is φ = 9523200.

The previous prime is 21434143. The next prime is 21434159. The reversal of 21434144 is 44143412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21049744 + 384400 = 4588^2 + 620^2 .

It is not an unprimeable number, because it can be changed into a prime (21434143) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 522764 + ... + 522804.

Almost surely, 2^21434144 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 21434144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23647302).

21434144 is an abundant number, since it is smaller than the sum of its proper divisors (25860460).

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

21434144 is a wasteful number, since it uses less digits than its factorization.

21434144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130 (or 91 counting only the distinct ones).

The product of its digits is 1536, while the sum is 23.

The square root of 21434144 is about 4629.7023662434. The cubic root of 21434144 is about 277.7806872347.

Adding to 21434144 its reverse (44143412), we get a palindrome (65577556).

The spelling of 21434144 in words is "twenty-one million, four hundred thirty-four thousand, one hundred forty-four".