21707648 has 16 divisors (see below), whose sum is σ = 43245960. Its totient is φ = 10853760.

The previous prime is 21707603. The next prime is 21707701. The reversal of 21707648 is 84670712.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (16).

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 as a sum of consecutive naturals, namely, 84668 + ... + 84923.

Almost surely, 2^21707648 is an apocalyptic number.

It is an amenable number.

21707648 is a deficient number, since it is larger than the sum of its proper divisors (21538312).

21707648 is an equidigital number, since it uses as much as digits as its factorization.

21707648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169605 (or 169593 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 21707648 is about 4659.1467029919. The cubic root of 21707648 is about 278.9572096432.

The spelling of 21707648 in words is "twenty-one million, seven hundred seven thousand, six hundred forty-eight".