21210423424 has 32 divisors (see below), whose sum is σ = 42360617340. Its totient is φ = 10578739200.

The previous prime is 21210423391. The next prime is 21210423427. The reversal of 21210423424 is 42432401212.

It can be written as a sum of positive squares in 2 ways, for example, as 15219663424 + 5990760000 = 123368^2 + 77400^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (21210423427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155289 + ... + 257944.

Almost surely, 2^21210423424 is an apocalyptic number.

It is an amenable number.

21210423424 is a deficient number, since it is larger than the sum of its proper divisors (21150193916).

21210423424 is an equidigital number, since it uses as much as digits as its factorization.

21210423424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 413648 (or 413636 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 25.

Adding to 21210423424 its reverse (42432401212), we get a palindrome (63642824636).

The spelling of 21210423424 in words is "twenty-one billion, two hundred ten million, four hundred twenty-three thousand, four hundred twenty-four".