20121100020 has 144 divisors (see below), whose sum is σ = 70143615360. Its totient is φ = 4573363968.

The previous prime is 20121100003. The next prime is 20121100079. The reversal of 20121100020 is 2000112102.

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 = 20121099975 and 20121100011.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 180934 + ... + 270146.

It is an arithmetic number, because the mean of its divisors is an integer number (487108440).

Almost surely, 2^20121100020 is an apocalyptic number.

20121100020 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 20121100020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35071807680).

20121100020 is an abundant number, since it is smaller than the sum of its proper divisors (50022515340).

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

20121100020 is a wasteful number, since it uses less digits than its factorization.

20121100020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89414 (or 89409 counting only the distinct ones).

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

Adding to 20121100020 its reverse (2000112102), we get a palindrome (22121212122).

The spelling of 20121100020 in words is "twenty billion, one hundred twenty-one million, one hundred thousand, twenty".