21044004320 has 48 divisors (see below), whose sum is σ = 49922844048. Its totient is φ = 8382658560.

The previous prime is 21044004313. The next prime is 21044004337. The reversal of 21044004320 is 2340044012.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21044004292 and 21044004301.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 234314 + ... + 311433.

It is an arithmetic number, because the mean of its divisors is an integer number (1040059251).

Almost surely, 2^21044004320 is an apocalyptic number.

21044004320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21044004320 is an abundant number, since it is smaller than the sum of its proper divisors (28878839728).

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

21044004320 is a wasteful number, since it uses less digits than its factorization.

21044004320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546003 (or 545995 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

Adding to 21044004320 its reverse (2340044012), we get a palindrome (23384048332).

The spelling of 21044004320 in words is "twenty-one billion, forty-four million, four thousand, three hundred twenty".