20109100 has 72 divisors (see below), whose sum is σ = 48340656. Its totient is φ = 7200000.

The previous prime is 20109073. The next prime is 20109109. The reversal of 20109100 is 190102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20109109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 111010 + ... + 111190.

It is an arithmetic number, because the mean of its divisors is an integer number (671398).

Almost surely, 2^20109100 is an apocalyptic number.

20109100 is a gapful number since it is divisible by the number (20) 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 20109100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24170328).

20109100 is an abundant number, since it is smaller than the sum of its proper divisors (28231556).

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

20109100 is a wasteful number, since it uses less digits than its factorization.

20109100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307 (or 300 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 13.

The square root of 20109100 is about 4484.3171163512. The cubic root of 20109100 is about 271.9344384951.

Adding to 20109100 its reverse (190102), we get a palindrome (20299202).

The spelling of 20109100 in words is "twenty million, one hundred nine thousand, one hundred".