21308268 has 12 divisors (see below), whose sum is σ = 49719320. Its totient is φ = 7102752.

The previous prime is 21308219. The next prime is 21308299. The reversal of 21308268 is 86280312.

It is a tau number, because it is divible by the number of its divisors (12).

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 3 ways as a sum of consecutive naturals, for example, 887833 + ... + 887856.

Almost surely, 2^21308268 is an apocalyptic number.

It is an amenable number.

21308268 is an abundant number, since it is smaller than the sum of its proper divisors (28411052).

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

21308268 is a wasteful number, since it uses less digits than its factorization.

21308268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1775696 (or 1775694 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 21308268 is about 4616.0879541014. The cubic root of 21308268 is about 277.2358463499.

The spelling of 21308268 in words is "twenty-one million, three hundred eight thousand, two hundred sixty-eight".