21212122212020 has 12 divisors (see below), whose sum is σ = 44545456645284. Its totient is φ = 8484848884800.

The previous prime is 21212122212007. The next prime is 21212122212031. The reversal of 21212122212020 is 2021222121212.

It can be written as a sum of positive squares in 2 ways, for example, as 2362405888144 + 18849716323876 = 1537012^2 + 4341626^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1060606110601 = 21212122212020 / (2 + 1 + 2 + 1 + 2 + 1 + 2 + 2 + 2 + 1 + 2 + 0 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 21212122211983 and 21212122212001.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 530303055281 + ... + 530303055320.

It is an arithmetic number, because the mean of its divisors is an integer number (3712121387107).

Almost surely, 2^{21212122212020} is an apocalyptic number.

21212122212020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212122212020 is an abundant number, since it is smaller than the sum of its proper divisors (23333334433264).

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

21212122212020 is a wasteful number, since it uses less digits than its factorization.

21212122212020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1060606110610 (or 1060606110608 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21212122212020 its reverse (2021222121212), we get a palindrome (23233344333232).

The spelling of 21212122212020 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty-two million, two hundred twelve thousand, twenty".