21704308 has 48 divisors (see below), whose sum is σ = 43001280. Its totient is φ = 9524736.

The previous prime is 21704303. The next prime is 21704317. The reversal of 21704308 is 80340712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21704303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 138166 + ... + 138322.

It is an arithmetic number, because the mean of its divisors is an integer number (895860).

Almost surely, 2^21704308 is an apocalyptic number.

It is an amenable number.

21704308 is a deficient number, since it is larger than the sum of its proper divisors (21296972).

21704308 is a wasteful number, since it uses less digits than its factorization.

21704308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304 (or 302 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 21704308 is about 4658.7882544713. The cubic root of 21704308 is about 278.9429018615.

The spelling of 21704308 in words is "twenty-one million, seven hundred four thousand, three hundred eight".