21031322220 has 96 divisors (see below), whose sum is σ = 65518488000. Its totient is φ = 5600835072.

The previous prime is 21031322173. The next prime is 21031322267. The reversal of 21031322220 is 2222313012.

It is an interprime number because it is at equal distance from previous prime (21031322173) and next prime (21031322267).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21031322193 and 21031322202.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 383056 + ... + 434504.

It is an arithmetic number, because the mean of its divisors is an integer number (682484250).

Almost surely, 2^21031322220 is an apocalyptic number.

21031322220 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 21031322220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32759244000).

21031322220 is an abundant number, since it is smaller than the sum of its proper divisors (44487165780).

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

21031322220 is a wasteful number, since it uses less digits than its factorization.

21031322220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52224 (or 52216 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

Adding to 21031322220 its reverse (2222313012), we get a palindrome (23253635232).

The spelling of 21031322220 in words is "twenty-one billion, thirty-one million, three hundred twenty-two thousand, two hundred twenty".