21585047584 has 48 divisors (see below), whose sum is σ = 44906551200. Its totient is φ = 10184638464.

The previous prime is 21585047573. The next prime is 21585047587. The reversal of 21585047584 is 48574058512.

It is not an unprimeable number, because it can be changed into a prime (21585047587) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 87187 + ... + 225325.

It is an arithmetic number, because the mean of its divisors is an integer number (935553150).

Almost surely, 2^21585047584 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 21585047584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22453275600).

21585047584 is an abundant number, since it is smaller than the sum of its proper divisors (23321503616).

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

21585047584 is a wasteful number, since it uses less digits than its factorization.

21585047584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138425 (or 138417 counting only the distinct ones).

The product of its (nonzero) digits is 1792000, while the sum is 49.

The spelling of 21585047584 in words is "twenty-one billion, five hundred eighty-five million, forty-seven thousand, five hundred eighty-four".