21908316 has 12 divisors (see below), whose sum is σ = 51119432. Its totient is φ = 7302768.

The previous prime is 21908303. The next prime is 21908317. The reversal of 21908316 is 61380912.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21908317) 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 3 ways as a sum of consecutive naturals, for example, 912835 + ... + 912858.

Almost surely, 2^21908316 is an apocalyptic number.

It is an amenable number.

21908316 is an abundant number, since it is smaller than the sum of its proper divisors (29211116).

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

21908316 is a wasteful number, since it uses less digits than its factorization.

21908316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1825700 (or 1825698 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21908316 is about 4680.6320086074. The cubic root of 21908316 is about 279.8141453707.

The spelling of 21908316 in words is "twenty-one million, nine hundred eight thousand, three hundred sixteen".