21000013424 has 20 divisors (see below), whose sum is σ = 43817336136. Its totient is φ = 9692313792.

The previous prime is 21000013421. The next prime is 21000013439. The reversal of 21000013424 is 42431000012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000013421) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 50480594 + ... + 50481009.

Almost surely, 2^21000013424 is an apocalyptic number.

It is an amenable number.

21000013424 is an abundant number, since it is smaller than the sum of its proper divisors (22817322712).

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

21000013424 is a wasteful number, since it uses less digits than its factorization.

21000013424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100961624 (or 100961618 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 21000013424 its reverse (42431000012), we get a palindrome (63431013436).

The spelling of 21000013424 in words is "twenty-one billion, thirteen thousand, four hundred twenty-four".