20100100 has 72 divisors (see below), whose sum is σ = 46872000. Its totient is φ = 7459200.

The previous prime is 20100097. The next prime is 20100149. The reversal of 20100100 is 100102.

It is a Harshad number since it is a multiple of its sum of digits (4).

It is a self number, because there is not a number n which added to its sum of digits gives 20100100.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 134826 + ... + 134974.

It is an arithmetic number, because the mean of its divisors is an integer number (651000).

Almost surely, 2^20100100 is an apocalyptic number.

20100100 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 20100100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23436000).

20100100 is an abundant number, since it is smaller than the sum of its proper divisors (26771900).

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

20100100 is a wasteful number, since it uses less digits than its factorization.

20100100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253 (or 246 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 4.

The square root of 20100100 is about 4483.3135067715. The cubic root of 20100100 is about 271.8938635786.

Adding to 20100100 its reverse (100102), we get a palindrome (20200202).

The spelling of 20100100 in words is "twenty million, one hundred thousand, one hundred".