21047545728 has 384 divisors, whose sum is σ = 68892595200. Its totient is φ = 6110208000.

The previous prime is 21047545721. The next prime is 21047545747. The reversal of 21047545728 is 82754574012.

21047545728 is a `hidden beast` number, since 2 + 1 + 0 + 4 + 75 + 4 + 572 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21047545721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 51460788 + ... + 51461196.

It is an arithmetic number, because the mean of its divisors is an integer number (179407800).

Almost surely, 2^21047545728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21047545728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34446297600).

21047545728 is an abundant number, since it is smaller than the sum of its proper divisors (47845049472).

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

21047545728 is a wasteful number, since it uses less digits than its factorization.

21047545728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602 (or 587 counting only the distinct ones).

The product of its (nonzero) digits is 627200, while the sum is 45.

The spelling of 21047545728 in words is "twenty-one billion, forty-seven million, five hundred forty-five thousand, seven hundred twenty-eight".