21220004424 has 64 divisors (see below), whose sum is σ = 55978646400. Its totient is φ = 6689762816.

The previous prime is 21220004389. The next prime is 21220004437. The reversal of 21220004424 is 42440002212.

It is a self number, because there is not a number n which added to its sum of digits gives 21220004424.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 166839 + ... + 265094.

It is an arithmetic number, because the mean of its divisors is an integer number (874666350).

Almost surely, 2^21220004424 is an apocalyptic number.

21220004424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21220004424 is an abundant number, since it is smaller than the sum of its proper divisors (34758641976).

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

21220004424 is a wasteful number, since it uses less digits than its factorization.

21220004424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432054 (or 432050 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 21.

Adding to 21220004424 its reverse (42440002212), we get a palindrome (63660006636).

The spelling of 21220004424 in words is "twenty-one billion, two hundred twenty million, four thousand, four hundred twenty-four".