21120324544 has 56 divisors (see below), whose sum is σ = 48410183088. Its totient is φ = 9035427840.

The previous prime is 21120324541. The next prime is 21120324553. The reversal of 21120324544 is 44542302112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120324541) 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, 870399 + ... + 894334.

Almost surely, 2^21120324544 is an apocalyptic number.

It is an amenable number.

21120324544 is an abundant number, since it is smaller than the sum of its proper divisors (27289858544).

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

21120324544 is a wasteful number, since it uses less digits than its factorization.

21120324544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1764773 (or 1764763 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 28.

Adding to 21120324544 its reverse (44542302112), we get a palindrome (65662626656).

The spelling of 21120324544 in words is "twenty-one billion, one hundred twenty million, three hundred twenty-four thousand, five hundred forty-four".