21540024000 has 336 divisors, whose sum is σ = 84060097056. Its totient is φ = 5221632000.

The previous prime is 21540023993. The next prime is 21540024017. The reversal of 21540024000 is 42004512.

21540024000 is a `hidden beast` number, since 21 + 5 + 400 + 240 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 778402 + ... + 805598.

Almost surely, 2^21540024000 is an apocalyptic number.

21540024000 is a gapful number since it is divisible by the number (20) 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 21540024000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42030048528).

21540024000 is an abundant number, since it is smaller than the sum of its proper divisors (62520073056).

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

21540024000 is a wasteful number, since it uses less digits than its factorization.

21540024000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27241 (or 27218 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

Adding to 21540024000 its reverse (42004512), we get a palindrome (21582028512).

The spelling of 21540024000 in words is "twenty-one billion, five hundred forty million, twenty-four thousand".