21124203212 has 36 divisors (see below), whose sum is σ = 43016004864. Its totient is φ = 9050459040.

The previous prime is 21124203203. The next prime is 21124203223. The reversal of 21124203212 is 21230242112.

It is a super-2 number, since 2×21124203212² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 706037 + ... + 735347.

It is an arithmetic number, because the mean of its divisors is an integer number (1194889024).

Almost surely, 2^21124203212 is an apocalyptic number.

It is an amenable number.

21124203212 is an abundant number, since it is smaller than the sum of its proper divisors (21891801652).

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

21124203212 is a wasteful number, since it uses less digits than its factorization.

21124203212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33006 (or 32997 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21124203212 its reverse (21230242112), we get a palindrome (42354445324).

The spelling of 21124203212 in words is "twenty-one billion, one hundred twenty-four million, two hundred three thousand, two hundred twelve".