21128108 has 12 divisors (see below), whose sum is σ = 37043160. Its totient is φ = 10544352.

The previous prime is 21128087. The next prime is 21128117. The reversal of 21128108 is 80182112.

It is a happy 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 in 3 ways as a sum of consecutive naturals, for example, 2366 + ... + 6917.

It is an arithmetic number, because the mean of its divisors is an integer number (3086930).

Almost surely, 2^21128108 is an apocalyptic number.

It is an amenable number.

21128108 is a deficient number, since it is larger than the sum of its proper divisors (15915052).

21128108 is a wasteful number, since it uses less digits than its factorization.

21128108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9856 (or 9854 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 23.

The square root of 21128108 is about 4596.5321711046. The cubic root of 21128108 is about 276.4522969676.

The spelling of 21128108 in words is "twenty-one million, one hundred twenty-eight thousand, one hundred eight".