21253212224 has 28 divisors (see below), whose sum is σ = 42889170000. Its totient is φ = 10446492288.

The previous prime is 21253212181. The next prime is 21253212247. The reversal of 21253212224 is 42221235212.

It is a junction number, because it is equal to n+sod(n) for n = 21253212193 and 21253212202.

It is an unprimeable number.

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, 2810474 + ... + 2818025.

Almost surely, 2^21253212224 is an apocalyptic number.

It is an amenable number.

21253212224 is an abundant number, since it is smaller than the sum of its proper divisors (21635957776).

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

21253212224 is an equidigital number, since it uses as much as digits as its factorization.

21253212224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5628570 (or 5628560 counting only the distinct ones).

The product of its digits is 3840, while the sum is 26.

Adding to 21253212224 its reverse (42221235212), we get a palindrome (63474447436).

The spelling of 21253212224 in words is "twenty-one billion, two hundred fifty-three million, two hundred twelve thousand, two hundred twenty-four".