21535648 has 24 divisors (see below), whose sum is σ = 42545412. Its totient is φ = 10730496.

The previous prime is 21535643. The next prime is 21535663. The reversal of 21535648 is 84653512.

It can be written as a sum of positive squares in 2 ways, for example, as 17740944 + 3794704 = 4212^2 + 1948^2 .

It is not an unprimeable number, because it can be changed into a prime (21535643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9786 + ... + 11782.

Almost surely, 2^21535648 is an apocalyptic number.

It is an amenable number.

21535648 is a deficient number, since it is larger than the sum of its proper divisors (21009764).

21535648 is a wasteful number, since it uses less digits than its factorization.

21535648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2344 (or 2336 counting only the distinct ones).

The product of its digits is 28800, while the sum is 34.

The square root of 21535648 is about 4640.6516783745. The cubic root of 21535648 is about 278.2184849732.

The spelling of 21535648 in words is "twenty-one million, five hundred thirty-five thousand, six hundred forty-eight".