21241520 has 40 divisors (see below), whose sum is σ = 50026560. Its totient is φ = 8386560.

The previous prime is 21241513. The next prime is 21241529. The reversal of 21241520 is 2514212.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (21241529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4640 + ... + 8000.

It is an arithmetic number, because the mean of its divisors is an integer number (1250664).

Almost surely, 2^21241520 is an apocalyptic number.

21241520 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 21241520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25013280).

21241520 is an abundant number, since it is smaller than the sum of its proper divisors (28785040).

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

21241520 is a wasteful number, since it uses less digits than its factorization.

21241520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3453 (or 3447 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 21241520 is about 4608.8523517249. The cubic root of 21241520 is about 276.9460637772.

Adding to 21241520 its reverse (2514212), we get a palindrome (23755732).

The spelling of 21241520 in words is "twenty-one million, two hundred forty-one thousand, five hundred twenty".