21333335424 has 128 divisors (see below), whose sum is σ = 58871340000. Its totient is φ = 6836551680.

The previous prime is 21333335389. The next prime is 21333335431. The reversal of 21333335424 is 42453333312.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×21333335424² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 2679802 + ... + 2687750.

Almost surely, 2^21333335424 is an apocalyptic number.

21333335424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21333335424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29435670000).

21333335424 is an abundant number, since it is smaller than the sum of its proper divisors (37538004576).

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

21333335424 is a wasteful number, since it uses less digits than its factorization.

21333335424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8236 (or 8224 counting only the distinct ones).

The product of its digits is 77760, while the sum is 33.

Adding to 21333335424 its reverse (42453333312), we get a palindrome (63786668736).

The spelling of 21333335424 in words is "twenty-one billion, three hundred thirty-three million, three hundred thirty-five thousand, four hundred twenty-four".