21584509272 has 48 divisors (see below), whose sum is σ = 61896758040. Its totient is φ = 6771610368.

The previous prime is 21584509259. The next prime is 21584509339. The reversal of 21584509272 is 27290548512.

21584509272 is a `hidden beast` number, since 21 + 58 + 4 + 509 + 2 + 72 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8815978 + ... + 8818425.

Almost surely, 2^21584509272 is an apocalyptic number.

It is an amenable number.

21584509272 is an abundant number, since it is smaller than the sum of its proper divisors (40312248768).

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

21584509272 is a wasteful number, since it uses less digits than its factorization.

21584509272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17634432 (or 17634425 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 21584509272 in words is "twenty-one billion, five hundred eighty-four million, five hundred nine thousand, two hundred seventy-two".