21524416 has 56 divisors (see below), whose sum is σ = 46492160. Its totient is φ = 9849600.

The previous prime is 21524401. The next prime is 21524423. The reversal of 21524416 is 61442512.

It is a happy number.

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, 37411 + ... + 37981.

Almost surely, 2^21524416 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 21524416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23246080).

21524416 is an abundant number, since it is smaller than the sum of its proper divisors (24967744).

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

21524416 is a wasteful number, since it uses less digits than its factorization.

21524416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633 (or 623 counting only the distinct ones).

The product of its digits is 1920, while the sum is 25.

The square root of 21524416 is about 4639.4413456795. The cubic root of 21524416 is about 278.1701079217.

Adding to 21524416 its reverse (61442512), we get a palindrome (82966928).

The spelling of 21524416 in words is "twenty-one million, five hundred twenty-four thousand, four hundred sixteen".