21108830920 has 32 divisors (see below), whose sum is σ = 47622235320. Its totient is φ = 8420889600.

The previous prime is 21108830917. The next prime is 21108830947. The reversal of 21108830920 is 2903880112.

It can be written as a sum of positive squares in 4 ways, for example, as 19216058884 + 1892772036 = 138622^2 + 43506^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 692481 + ... + 722320.

Almost surely, 2^21108830920 is an apocalyptic number.

21108830920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21108830920 is an abundant number, since it is smaller than the sum of its proper divisors (26513404400).

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

21108830920 is a wasteful number, since it uses less digits than its factorization.

21108830920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1415185 (or 1415181 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 34.

The spelling of 21108830920 in words is "twenty-one billion, one hundred eight million, eight hundred thirty thousand, nine hundred twenty".