21212221102020 has 576 divisors, whose sum is σ = 73886243558400. Its totient is φ = 4882611778560.

The previous prime is 21212221101991. The next prime is 21212221102021. The reversal of 21212221102020 is 2020112221212.

It is a happy number.

21212221102020 is a `hidden beast` number, since 21 + 212 + 221 + 10 + 202 + 0 = 666.

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 = 21212221101984 and 21212221102002.

It is not an unprimeable number, because it can be changed into a prime (21212221102021) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 5797270951 + ... + 5797274609.

It is an arithmetic number, because the mean of its divisors is an integer number (128274728400).

Almost surely, 2^{21212221102020} is an apocalyptic number.

21212221102020 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 21212221102020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36943121779200).

21212221102020 is an abundant number, since it is smaller than the sum of its proper divisors (52674022456380).

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

21212221102020 is a wasteful number, since it uses less digits than its factorization.

21212221102020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5360 (or 5355 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21212221102020 its reverse (2020112221212), we get a palindrome (23232333323232).

The spelling of 21212221102020 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty-one million, one hundred two thousand, twenty".