21231210220 has 24 divisors (see below), whose sum is σ = 48638773008. Its totient is φ = 7720440000.

The previous prime is 21231210197. The next prime is 21231210229. The reversal of 21231210220 is 2201213212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21231210194 and 21231210203.

It is not an unprimeable number, because it can be changed into a prime (21231210229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48252531 + ... + 48252970.

It is an arithmetic number, because the mean of its divisors is an integer number (2026615542).

Almost surely, 2^21231210220 is an apocalyptic number.

21231210220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21231210220 is an abundant number, since it is smaller than the sum of its proper divisors (27407562788).

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

21231210220 is a wasteful number, since it uses less digits than its factorization.

21231210220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96505521 (or 96505519 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21231210220 its reverse (2201213212), we get a palindrome (23432423432).

The spelling of 21231210220 in words is "twenty-one billion, two hundred thirty-one million, two hundred ten thousand, two hundred twenty".