20102100100020 has 144 divisors (see below), whose sum is σ = 61489374972480. Its totient is φ = 5315554073088.

The previous prime is 20102100100001. The next prime is 20102100100021. The reversal of 20102100100020 is 2000100120102.

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

It is a junction number, because it is equal to n+sod(n) for n = 20102100099975 and 20102100100011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20102100100021) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 20205784 + ... + 21177296.

It is an arithmetic number, because the mean of its divisors is an integer number (427009548420).

Almost surely, 2^{20102100100020} is an apocalyptic number.

20102100100020 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 20102100100020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30744687486240).

20102100100020 is an abundant number, since it is smaller than the sum of its proper divisors (41387274872460).

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

20102100100020 is a wasteful number, since it uses less digits than its factorization.

20102100100020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972494 (or 972489 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 20102100100020 its reverse (2000100120102), we get a palindrome (22102200220122).

The spelling of 20102100100020 in words is "twenty trillion, one hundred two billion, one hundred million, one hundred thousand, twenty".