21002223424 has 56 divisors (see below), whose sum is σ = 51293906048. Its totient is φ = 8308569600.

The previous prime is 21002223421. The next prime is 21002223433. The reversal of 21002223424 is 42432220012.

It is a tau number, because it is divible by the number of its divisors (56).

It is a super-2 number, since 2×21002223424² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21002223395 and 21002223404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002223421) 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, 1797252 + ... + 1808899.

It is an arithmetic number, because the mean of its divisors is an integer number (915962608).

Almost surely, 2^21002223424 is an apocalyptic number.

It is an amenable number.

21002223424 is an abundant number, since it is smaller than the sum of its proper divisors (30291682624).

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

21002223424 is a wasteful number, since it uses less digits than its factorization.

21002223424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3606183 (or 3606173 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21002223424 its reverse (42432220012), we get a palindrome (63434443436).

The spelling of 21002223424 in words is "twenty-one billion, two million, two hundred twenty-three thousand, four hundred twenty-four".