21441520 has 80 divisors (see below), whose sum is σ = 53425152. Its totient is φ = 7983360.

The previous prime is 21441493. The next prime is 21441523. The reversal of 21441520 is 2514412.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21441523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78985 + ... + 79255.

Almost surely, 2^21441520 is an apocalyptic number.

21441520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21441520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26712576).

21441520 is an abundant number, since it is smaller than the sum of its proper divisors (31983632).

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

21441520 is a wasteful number, since it uses less digits than its factorization.

21441520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350 (or 344 counting only the distinct ones).

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

The square root of 21441520 is about 4630.4988932079. The cubic root of 21441520 is about 277.8125472329.

Adding to 21441520 its reverse (2514412), we get a palindrome (23955932).

The spelling of 21441520 in words is "twenty-one million, four hundred forty-one thousand, five hundred twenty".