21404333424 has 80 divisors (see below), whose sum is σ = 55525017600. Its totient is φ = 7105114368.

The previous prime is 21404333411. The next prime is 21404333437. The reversal of 21404333424 is 42433340412.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21404333411) and next prime (21404333437).

It is a junction number, because it is equal to n+sod(n) for n = 21404333391 and 21404333400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21129142 + ... + 21130154.

It is an arithmetic number, because the mean of its divisors is an integer number (694062720).

Almost surely, 2^21404333424 is an apocalyptic number.

21404333424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21404333424 is an abundant number, since it is smaller than the sum of its proper divisors (34120684176).

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

21404333424 is a wasteful number, since it uses less digits than its factorization.

21404333424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2422 (or 2416 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 30.

Adding to 21404333424 its reverse (42433340412), we get a palindrome (63837673836).

The spelling of 21404333424 in words is "twenty-one billion, four hundred four million, three hundred thirty-three thousand, four hundred twenty-four".