21043511424 has 256 divisors, whose sum is σ = 68698224000. Its totient is φ = 6299430912.

The previous prime is 21043511407. The next prime is 21043511443. The reversal of 21043511424 is 42411534012.

21043511424 is a `hidden beast` number, since 2 + 104 + 3 + 511 + 42 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1656007 + ... + 1668665.

Almost surely, 2^21043511424 is an apocalyptic number.

21043511424 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 21043511424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34349112000).

21043511424 is an abundant number, since it is smaller than the sum of its proper divisors (47654712576).

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

21043511424 is a wasteful number, since it uses less digits than its factorization.

21043511424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12732 (or 12714 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The spelling of 21043511424 in words is "twenty-one billion, forty-three million, five hundred eleven thousand, four hundred twenty-four".