212121102220020 has 384 divisors, whose sum is σ = 756929224396800. Its totient is φ = 48310082726400.

The previous prime is 212121102220007. The next prime is 212121102220067. The reversal of 212121102220020 is 20022201121212.

It is a happy number.

212121102220020 is a `hidden beast` number, since 212 + 1 + 211 + 0 + 2 + 220 + 0 + 20 = 666.

It is a super-3 number, since 3×212121102220020³ (a number of 44 digits) contains 333 as substring.

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 = 212121102219975 and 212121102220002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2178255691 + ... + 2178353069.

It is an arithmetic number, because the mean of its divisors is an integer number (1971169855200).

Almost surely, 2^{212121102220020} is an apocalyptic number.

212121102220020 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 212121102220020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (378464612198400).

212121102220020 is an abundant number, since it is smaller than the sum of its proper divisors (544808122176780).

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

212121102220020 is a wasteful number, since it uses less digits than its factorization.

212121102220020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99476 (or 99468 counting only the distinct ones).

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

Adding to 212121102220020 its reverse (20022201121212), we get a palindrome (232143303341232).

The spelling of 212121102220020 in words is "two hundred twelve trillion, one hundred twenty-one billion, one hundred two million, two hundred twenty thousand, twenty".