21101201020 has 24 divisors (see below), whose sum is σ = 44362857168. Its totient is φ = 8430892800.

The previous prime is 21101200997. The next prime is 21101201039. The reversal of 21101201020 is 2010210112.

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 = 21101200988 and 21101201006.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 581166 + ... + 616405.

It is an arithmetic number, because the mean of its divisors is an integer number (1848452382).

Almost surely, 2^21101201020 is an apocalyptic number.

21101201020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101201020 is an abundant number, since it is smaller than the sum of its proper divisors (23261656148).

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

21101201020 is a wasteful number, since it uses less digits than its factorization.

21101201020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1198461 (or 1198459 counting only the distinct ones).

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

Adding to 21101201020 its reverse (2010210112), we get a palindrome (23111411132).

The spelling of 21101201020 in words is "twenty-one billion, one hundred one million, two hundred one thousand, twenty".