21222021202120 has 128 divisors (see below), whose sum is σ = 51391792902240. Its totient is φ = 7857784995840.

The previous prime is 21222021202097. The next prime is 21222021202189. The reversal of 21222021202120 is 2120212022212.

It can be written as a sum of positive squares in 16 ways, for example, as 5859023573764 + 15362997628356 = 2420542^2 + 3919566^2 .

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, 778690414 + ... + 778717666.

Almost surely, 2^{21222021202120} is an apocalyptic number.

21222021202120 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 21222021202120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25695896451120).

21222021202120 is an abundant number, since it is smaller than the sum of its proper divisors (30169771700120).

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

21222021202120 is a wasteful number, since it uses less digits than its factorization.

21222021202120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46115 (or 46111 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21222021202120 its reverse (2120212022212), we get a palindrome (23342233224332).

The spelling of 21222021202120 in words is "twenty-one trillion, two hundred twenty-two billion, twenty-one million, two hundred two thousand, one hundred twenty".