21304424440 has 32 divisors (see below), whose sum is σ = 51622260480. Its totient is φ = 7866248832.

The previous prime is 21304424437. The next prime is 21304424441. The reversal of 21304424440 is 4442440312.

It is a junction number, because it is equal to n+sod(n) for n = 21304424399 and 21304424408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304424441) 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, 20484504 + ... + 20485543.

It is an arithmetic number, because the mean of its divisors is an integer number (1613195640).

Almost surely, 2^21304424440 is an apocalyptic number.

21304424440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21304424440 is an abundant number, since it is smaller than the sum of its proper divisors (30317836040).

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

21304424440 is a wasteful number, since it uses less digits than its factorization.

21304424440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40970071 (or 40970067 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 28.

Adding to 21304424440 its reverse (4442440312), we get a palindrome (25746864752).

The spelling of 21304424440 in words is "twenty-one billion, three hundred four million, four hundred twenty-four thousand, four hundred forty".