20891108 has 48 divisors (see below), whose sum is σ = 44513280. Its totient is φ = 8379936.

The previous prime is 20891093. The next prime is 20891131. The reversal of 20891108 is 80119802.

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, 56741 + ... + 57107.

It is an arithmetic number, because the mean of its divisors is an integer number (927360).

Almost surely, 2^20891108 is an apocalyptic number.

20891108 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20891108, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22256640).

20891108 is an abundant number, since it is smaller than the sum of its proper divisors (23622172).

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

20891108 is a wasteful number, since it uses less digits than its factorization.

20891108 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 504 (or 502 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 20891108 is about 4570.6791617877. The cubic root of 20891108 is about 275.4147263048.

The spelling of 20891108 in words is "twenty million, eight hundred ninety-one thousand, one hundred eight".