21221330424 has 64 divisors (see below), whose sum is σ = 61869792000. Its totient is φ = 6063234912.

The previous prime is 21221330423. The next prime is 21221330467. The reversal of 21221330424 is 42403312212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 21221330394 and 21221330403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221330423) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1280722 + ... + 1297185.

It is an arithmetic number, because the mean of its divisors is an integer number (966715500).

Almost surely, 2^21221330424 is an apocalyptic number.

21221330424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21221330424 is an abundant number, since it is smaller than the sum of its proper divisors (40648461576).

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

21221330424 is a wasteful number, since it uses less digits than its factorization.

21221330424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2577937 (or 2577919 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21221330424 its reverse (42403312212), we get a palindrome (63624642636).

The spelling of 21221330424 in words is "twenty-one billion, two hundred twenty-one million, three hundred thirty thousand, four hundred twenty-four".