21231024020 has 48 divisors (see below), whose sum is σ = 46119803520. Its totient is φ = 8203400064.

The previous prime is 21231024013. The next prime is 21231024029. The reversal of 21231024020 is 2042013212.

It is a self number, because there is not a number n which added to its sum of digits gives 21231024020.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231024029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 344 + ... + 206063.

It is an arithmetic number, because the mean of its divisors is an integer number (960829240).

Almost surely, 2^21231024020 is an apocalyptic number.

21231024020 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 21231024020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23059901760).

21231024020 is an abundant number, since it is smaller than the sum of its proper divisors (24888779500).

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

21231024020 is a wasteful number, since it uses less digits than its factorization.

21231024020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206592 (or 206590 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 21231024020 its reverse (2042013212), we get a palindrome (23273037232).

The spelling of 21231024020 in words is "twenty-one billion, two hundred thirty-one million, twenty-four thousand, twenty".