21423204424 has 8 divisors (see below), whose sum is σ = 40168508310. Its totient is φ = 10711602208.

The previous prime is 21423204409. The next prime is 21423204493. The reversal of 21423204424 is 42440232412.

It can be written as a sum of positive squares in only one way, i.e., 15871464324 + 5551740100 = 125982^2 + 74510^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 21423204392 and 21423204401.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1338950269 + ... + 1338950284.

Almost surely, 2^21423204424 is an apocalyptic number.

It is an amenable number.

21423204424 is a deficient number, since it is larger than the sum of its proper divisors (18745303886).

21423204424 is a wasteful number, since it uses less digits than its factorization.

21423204424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2677900559 (or 2677900555 counting only the distinct ones).

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

Adding to 21423204424 its reverse (42440232412), we get a palindrome (63863436836).

The spelling of 21423204424 in words is "twenty-one billion, four hundred twenty-three million, two hundred four thousand, four hundred twenty-four".