21108164 has 48 divisors (see below), whose sum is σ = 48491520. Its totient is φ = 7788960.

The previous prime is 21108163. The next prime is 21108173. The reversal of 21108164 is 46180112.

21108164 = T₈₅ + T₈₆ + ... + T₅₀₂.

It is not an unprimeable number, because it can be changed into a prime (21108163) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4049 + ... + 7655.

It is an arithmetic number, because the mean of its divisors is an integer number (1010240).

Almost surely, 2^21108164 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21108164, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24245760).

21108164 is an abundant number, since it is smaller than the sum of its proper divisors (27383356).

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

21108164 is a wasteful number, since it uses less digits than its factorization.

21108164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3648 (or 3646 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 21108164 is about 4594.3621973023. The cubic root of 21108164 is about 276.3652833335.

Adding to 21108164 its reverse (46180112), we get a palindrome (67288276).

The spelling of 21108164 in words is "twenty-one million, one hundred eight thousand, one hundred sixty-four".