21212122222120 has 16 divisors (see below), whose sum is σ = 47727274999860. Its totient is φ = 8484848888832.

The previous prime is 21212122222103. The next prime is 21212122222139. The reversal of 21212122222120 is 2122222121212.

It can be written as a sum of positive squares in 2 ways, for example, as 20023136977284 + 1188985244836 = 4474722^2 + 1090406^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21212122222091 and 21212122222100.

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, 265151527737 + ... + 265151527816.

Almost surely, 2^{21212122222120} is an apocalyptic number.

21212122222120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212122222120 is an abundant number, since it is smaller than the sum of its proper divisors (26515152777740).

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

21212122222120 is a wasteful number, since it uses less digits than its factorization.

21212122222120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530303055564 (or 530303055560 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

Adding to 21212122222120 its reverse (2122222121212), we get a palindrome (23334344343332).

The spelling of 21212122222120 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty-two million, two hundred twenty-two thousand, one hundred twenty".