2100100020 has 96 divisors (see below), whose sum is σ = 6357187200. Its totient is φ = 516201984.

The previous prime is 2100099979. The next prime is 2100100033. The reversal of 2100100020 is 200010012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a junction number, because it is equal to n+sod(n) for n = 2100099981 and 2100100008.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17286 + ... + 67074.

It is an arithmetic number, because the mean of its divisors is an integer number (66220700).

Almost surely, 2^2100100020 is an apocalyptic number.

2100100020 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 2100100020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3178593600).

2100100020 is an abundant number, since it is smaller than the sum of its proper divisors (4257087180).

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

2100100020 is a wasteful number, since it uses less digits than its factorization.

2100100020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49857 (or 49855 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 2100100020 is about 45826.8482442334. The cubic root of 2100100020 is about 1280.5994953835.

Adding to 2100100020 its reverse (200010012), we get a palindrome (2300110032).

The spelling of 2100100020 in words is "two billion, one hundred million, one hundred thousand, twenty".