21543648 has 48 divisors (see below), whose sum is σ = 64632960. Its totient is φ = 6155136.

The previous prime is 21543619. The next prime is 21543653. The reversal of 21543648 is 84634512.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

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, 15358 + ... + 16701.

It is an arithmetic number, because the mean of its divisors is an integer number (1346520).

Almost surely, 2^21543648 is an apocalyptic number.

21543648 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21543648 is an abundant number, since it is smaller than the sum of its proper divisors (43089312).

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

21543648 is a wasteful number, since it uses less digits than its factorization.

21543648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32079 (or 32071 counting only the distinct ones).

The product of its digits is 23040, while the sum is 33.

The square root of 21543648 is about 4641.5135462476. The cubic root of 21543648 is about 278.2529313066.

The spelling of 21543648 in words is "twenty-one million, five hundred forty-three thousand, six hundred forty-eight".