21648000 has 256 divisors, whose sum is σ = 80196480. Its totient is φ = 5120000.

The previous prime is 21647993. The next prime is 21648001. The reversal of 21648000 is 84612.

It is not an unprimeable number, because it can be changed into a prime (21648001) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 527980 + ... + 528020.

Almost surely, 2^21648000 is an apocalyptic number.

21648000 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 21648000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40098240).

21648000 is an abundant number, since it is smaller than the sum of its proper divisors (58548480).

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

21648000 is a wasteful number, since it uses less digits than its factorization.

21648000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84 (or 62 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21648000 is about 4652.7411275505. The cubic root of 21648000 is about 278.7014702327.

The spelling of 21648000 in words is "twenty-one million, six hundred forty-eight thousand".