20101021100 has 72 divisors (see below), whose sum is σ = 44655141888. Its totient is φ = 7850286400.

The previous prime is 20101021099. The next prime is 20101021103. The reversal of 20101021100 is 112010102.

It is not an unprimeable number, because it can be changed into a prime (20101021103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2020739 + ... + 2030661.

It is an arithmetic number, because the mean of its divisors is an integer number (620210304).

Almost surely, 2^20101021100 is an apocalyptic number.

20101021100 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 20101021100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22327570944).

20101021100 is an abundant number, since it is smaller than the sum of its proper divisors (24554120788).

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

20101021100 is a wasteful number, since it uses less digits than its factorization.

20101021100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10415 (or 10408 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 20101021100 its reverse (112010102), we get a palindrome (20213031202).

The spelling of 20101021100 in words is "twenty billion, one hundred one million, twenty-one thousand, one hundred".