21144020224 has 72 divisors (see below), whose sum is σ = 42781737600. Its totient is φ = 10428672000.

The previous prime is 21144020207. The next prime is 21144020257. The reversal of 21144020224 is 42202044112.

It is a junction number, because it is equal to n+sod(n) for n = 21144020195 and 21144020204.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5757909 + ... + 5761579.

It is an arithmetic number, because the mean of its divisors is an integer number (594190800).

Almost surely, 2^21144020224 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21144020224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21390868800).

21144020224 is an abundant number, since it is smaller than the sum of its proper divisors (21637717376).

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

21144020224 is a wasteful number, since it uses less digits than its factorization.

21144020224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3987 (or 3973 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 22.

Adding to 21144020224 its reverse (42202044112), we get a palindrome (63346064336).

The spelling of 21144020224 in words is "twenty-one billion, one hundred forty-four million, twenty thousand, two hundred twenty-four".