21735648 has 96 divisors (see below), whose sum is σ = 69189120. Its totient is φ = 6583680.

The previous prime is 21735647. The next prime is 21735653. The reversal of 21735648 is 84653712.

21735648 is a `hidden beast` number, since 2 + 1 + 7 + 3 + 5 + 648 = 666.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21735643) 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 15 ways as a sum of consecutive naturals, for example, 8361 + ... + 10647.

It is an arithmetic number, because the mean of its divisors is an integer number (720720).

Almost surely, 2^21735648 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 21735648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34594560).

21735648 is an abundant number, since it is smaller than the sum of its proper divisors (47453472).

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

21735648 is a wasteful number, since it uses less digits than its factorization.

21735648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2317 (or 2303 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 21735648 is about 4662.1505767189. The cubic root of 21735648 is about 279.0770974354.

The spelling of 21735648 in words is "twenty-one million, seven hundred thirty-five thousand, six hundred forty-eight".