21212102220100 has 144 divisors (see below), whose sum is σ = 50953838745600. Its totient is φ = 7600108432000.

The previous prime is 21212102220079. The next prime is 21212102220187. The reversal of 21212102220100 is 102220121212.

It is a happy number.

It is a super-3 number, since 3×21212102220100³ (a number of 41 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 126360021 + ... + 126527779.

It is an arithmetic number, because the mean of its divisors is an integer number (353846102400).

Almost surely, 2^{21212102220100} is an apocalyptic number.

21212102220100 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 21212102220100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25476919372800).

21212102220100 is an abundant number, since it is smaller than the sum of its proper divisors (29741736525500).

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

21212102220100 is a wasteful number, since it uses less digits than its factorization.

21212102220100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169474 (or 169467 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21212102220100 its reverse (102220121212), we get a palindrome (21314322341312).

The spelling of 21212102220100 in words is "twenty-one trillion, two hundred twelve billion, one hundred two million, two hundred twenty thousand, one hundred".