21210110020 has 48 divisors (see below), whose sum is σ = 51147835200. Its totient is φ = 7306830720.

The previous prime is 21210110017. The next prime is 21210110021. The reversal of 21210110020 is 2001101212.

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 = 21210109979 and 21210110006.

It is not an unprimeable number, because it can be changed into a prime (21210110021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2532915 + ... + 2541274.

It is an arithmetic number, because the mean of its divisors is an integer number (1065579900).

Almost surely, 2^21210110020 is an apocalyptic number.

21210110020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210110020 is an abundant number, since it is smaller than the sum of its proper divisors (29937725180).

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

21210110020 is a wasteful number, since it uses less digits than its factorization.

21210110020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5074228 (or 5074226 counting only the distinct ones).

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

Adding to 21210110020 its reverse (2001101212), we get a palindrome (23211211232).

The spelling of 21210110020 in words is "twenty-one billion, two hundred ten million, one hundred ten thousand, twenty".