212121212121 has 144 divisors (see below), whose sum is σ = 398155696848. Its totient is φ = 107775360000.

The previous prime is 212121212101. The next prime is 212121212123. The reversal of 212121212121 is 121212121212.

212121212121 is a `hidden beast` number, since 212 + 121 + 212 + 121 = 666.

212121212121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

212121212121 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 8 ways, for example, as 71072894025 + 141048318096 = 266595^2 + 375564^2 .

It is not a de Polignac number, because 212121212121 - 2⁹ = 212121211609 is a prime.

It is an alternating number because its digits alternate between even and odd.

212121212121 is an undulating number in base 10.

212121212121 is a modest number, since divided by 21212121 gives 2121 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 212121212094 and 212121212103.

It is not an unprimeable number, because it can be changed into a prime (212121212123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 21419271 + ... + 21429171.

It is an arithmetic number, because the mean of its divisors is an integer number (2764970117).

Almost surely, 2^212121212121 is an apocalyptic number.

212121212121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

212121212121 is a deficient number, since it is larger than the sum of its proper divisors (186034484727).

212121212121 is a wasteful number, since it uses less digits than its factorization.

212121212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10072 (or 10062 counting only the distinct ones).

The product of its digits is 64, while the sum is 18.

Adding to 212121212121 its reverse (121212121212), we get a palindrome (333333333333).

Subtracting from 212121212121 its reverse (121212121212), we obtain a palindrome (90909090909).

It can be divided in two parts, 212121212 and 121, that multiplied together give a palindrome (25666666652).

The spelling of 212121212121 in words is "two hundred twelve billion, one hundred twenty-one million, two hundred twelve thousand, one hundred twenty-one".