20105100 has 108 divisors (see below), whose sum is σ = 63980280. Its totient is φ = 5280000.

The previous prime is 20105089. The next prime is 20105117. The reversal of 20105100 is 150102.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 79975 + ... + 80225.

It is an arithmetic number, because the mean of its divisors is an integer number (592410).

Almost surely, 2^20105100 is an apocalyptic number.

20105100 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 20105100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31990140).

20105100 is an abundant number, since it is smaller than the sum of its proper divisors (43875180).

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

20105100 is a wasteful number, since it uses less digits than its factorization.

20105100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360 (or 350 counting only the distinct ones).

The product of its (nonzero) digits is 10, while the sum is 9.

The square root of 20105100 is about 4483.8710953818. The cubic root of 20105100 is about 271.9164066938.

Adding to 20105100 its reverse (150102), we get a palindrome (20255202).

The spelling of 20105100 in words is "twenty million, one hundred five thousand, one hundred".