21288908 has 6 divisors (see below), whose sum is σ = 37255596. Its totient is φ = 10644452.

The previous prime is 21288907. The next prime is 21288923. The reversal of 21288908 is 80988212.

It is not an unprimeable number, because it can be changed into a prime (21288901) 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 as a sum of consecutive naturals, namely, 2661110 + ... + 2661117.

It is an arithmetic number, because the mean of its divisors is an integer number (6209266).

Almost surely, 2^21288908 is an apocalyptic number.

It is an amenable number.

21288908 is a deficient number, since it is larger than the sum of its proper divisors (15966688).

21288908 is a wasteful number, since it uses less digits than its factorization.

21288908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5322231 (or 5322229 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 38.

The square root of 21288908 is about 4613.9904637960. The cubic root of 21288908 is about 277.1518584144.

The spelling of 21288908 in words is "twenty-one million, two hundred eighty-eight thousand, nine hundred eight".