21423584 has 72 divisors (see below), whose sum is σ = 52888248. Its totient is φ = 8467200.

The previous prime is 21423581. The next prime is 21423593. The reversal of 21423584 is 48532412.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423581) 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, 19859 + ... + 20909.

It is an arithmetic number, because the mean of its divisors is an integer number (734559).

Almost surely, 2^21423584 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 21423584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26444124).

21423584 is an abundant number, since it is smaller than the sum of its proper divisors (31464664).

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

21423584 is a wasteful number, since it uses less digits than its factorization.

21423584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1088 (or 1073 counting only the distinct ones).

The product of its digits is 7680, while the sum is 29.

The square root of 21423584 is about 4628.5617636583. The cubic root of 21423584 is about 277.7350614967.

Adding to 21423584 its reverse (48532412), we get a palindrome (69955996).

The spelling of 21423584 in words is "twenty-one million, four hundred twenty-three thousand, five hundred eighty-four".