21444520 has 32 divisors (see below), whose sum is σ = 48382920. Its totient is φ = 8554240.

The previous prime is 21444499. The next prime is 21444541. The reversal of 21444520 is 2544412.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21444499) and next prime (21444541).

It can be written as a sum of positive squares in 4 ways, for example, as 12068676 + 9375844 = 3474^2 + 3062^2 .

It is a zygodrome in base 3.

It is a junction number, because it is equal to n+sod(n) for n = 21444491 and 21444500.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 25710 + ... + 26530.

Almost surely, 2^21444520 is an apocalyptic number.

21444520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21444520 is an abundant number, since it is smaller than the sum of its proper divisors (26938400).

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

21444520 is a wasteful number, since it uses less digits than its factorization.

21444520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1485 (or 1481 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 21444520 is about 4630.8228210546. The cubic root of 21444520 is about 277.8255033849.

Adding to 21444520 its reverse (2544412), we get a palindrome (23988932).

The spelling of 21444520 in words is "twenty-one million, four hundred forty-four thousand, five hundred twenty".