21224513020544 has 16 divisors (see below), whose sum is σ = 42283209533370. Its totient is φ = 10612256510208.

The previous prime is 21224513020481. The next prime is 21224513020547. The reversal of 21224513020544 is 44502031542212.

It can be written as a sum of positive squares in only one way, i.e., 14115890580544 + 7108622440000 = 3757112^2 + 2666200^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is not an unprimeable number, because it can be changed into a prime (21224513020547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82908253859 + ... + 82908254114.

Almost surely, 2^{21224513020544} is an apocalyptic number.

It is an amenable number.

21224513020544 is a deficient number, since it is larger than the sum of its proper divisors (21058696512826).

21224513020544 is an equidigital number, since it uses as much as digits as its factorization.

21224513020544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165816507987 (or 165816507975 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 35.

Adding to 21224513020544 its reverse (44502031542212), we get a palindrome (65726544562756).

The spelling of 21224513020544 in words is "twenty-one trillion, two hundred twenty-four billion, five hundred thirteen million, twenty thousand, five hundred forty-four".