21012108 has 48 divisors (see below), whose sum is σ = 53178720. Its totient is φ = 6457152.

The previous prime is 21012091. The next prime is 21012127. The reversal of 21012108 is 80121012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25966 + ... + 26762.

It is an arithmetic number, because the mean of its divisors is an integer number (1107890).

Almost surely, 2^21012108 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 21012108, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26589360).

21012108 is an abundant number, since it is smaller than the sum of its proper divisors (32166612).

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

21012108 is a wasteful number, since it uses less digits than its factorization.

21012108 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 843 (or 815 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

The square root of 21012108 is about 4583.8965956924. The cubic root of 21012108 is about 275.9454313458.

The spelling of 21012108 in words is "twenty-one million, twelve thousand, one hundred eight".