21165108 has 12 divisors (see below), whose sum is σ = 49385280. Its totient is φ = 7055032.

The previous prime is 21165097. The next prime is 21165121. The reversal of 21165108 is 80156112.

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

It is a congruent 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, 881868 + ... + 881891.

It is an arithmetic number, because the mean of its divisors is an integer number (4115440).

Almost surely, 2^21165108 is an apocalyptic number.

It is an amenable number.

21165108 is an abundant number, since it is smaller than the sum of its proper divisors (28220172).

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

21165108 is a wasteful number, since it uses less digits than its factorization.

21165108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1763766 (or 1763764 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 24.

The square root of 21165108 is about 4600.5551838881. Note that the first 3 decimals coincide. The cubic root of 21165108 is about 276.6135792724.

The spelling of 21165108 in words is "twenty-one million, one hundred sixty-five thousand, one hundred eight".