21000101102020 has 24 divisors (see below), whose sum is σ = 44101889659800. Its totient is φ = 8399720946432.

The previous prime is 21000101102009. The next prime is 21000101102021. The reversal of 21000101102020 is 2020110100012.

It can be written as a sum of positive squares in 4 ways, for example, as 261257965956 + 20738843136064 = 511134^2 + 4553992^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21000101101988 and 21000101102006.

It is not an unprimeable number, because it can be changed into a prime (21000101102021) 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 7 ways as a sum of consecutive naturals, for example, 19429065 + ... + 20481424.

It is an arithmetic number, because the mean of its divisors is an integer number (1837578735825).

Almost surely, 2^{21000101102020} is an apocalyptic number.

21000101102020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000101102020 is an abundant number, since it is smaller than the sum of its proper divisors (23101788557780).

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

21000101102020 is a wasteful number, since it uses less digits than its factorization.

21000101102020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39936807 (or 39936805 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21000101102020 its reverse (2020110100012), we get a palindrome (23020211202032).

The spelling of 21000101102020 in words is "twenty-one trillion, one hundred one million, one hundred two thousand, twenty".