21311221424 has 20 divisors (see below), whose sum is σ = 41299528536. Its totient is φ = 10653278592.

The previous prime is 21311221397. The next prime is 21311221441. The reversal of 21311221424 is 42412211312.

It is a self number, because there is not a number n which added to its sum of digits gives 21311221424.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69149 + ... + 217724.

Almost surely, 2^21311221424 is an apocalyptic number.

It is an amenable number.

21311221424 is a deficient number, since it is larger than the sum of its proper divisors (19988307112).

21311221424 is a wasteful number, since it uses less digits than its factorization.

21311221424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291524 (or 291518 counting only the distinct ones).

The product of its digits is 768, while the sum is 23.

Adding to 21311221424 its reverse (42412211312), we get a palindrome (63723432736).

The spelling of 21311221424 in words is "twenty-one billion, three hundred eleven million, two hundred twenty-one thousand, four hundred twenty-four".