21101210221212 has 216 divisors, whose sum is σ = 60634990935792. Its totient is φ = 6132596313600.

The previous prime is 21101210221193. The next prime is 21101210221243. The reversal of 21101210221212 is 21212201210112.

21101210221212 is a `hidden beast` number, since 2 + 110 + 121 + 0 + 221 + 212 = 666.

It is a super-2 number, since 2×21101210221212² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

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 71 ways as a sum of consecutive naturals, for example, 56330838 + ... + 56704194.

Almost surely, 2^{21101210221212} is an apocalyptic number.

21101210221212 is a gapful number since it is divisible by the number (22) 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 21101210221212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30317495467896).

21101210221212 is an abundant number, since it is smaller than the sum of its proper divisors (39533780714580).

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

21101210221212 is a wasteful number, since it uses less digits than its factorization.

21101210221212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 373537 (or 373473 counting only the distinct ones).

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

Adding to 21101210221212 its reverse (21212201210112), we get a palindrome (42313411431324).

The spelling of 21101210221212 in words is "twenty-one trillion, one hundred one billion, two hundred ten million, two hundred twenty-one thousand, two hundred twelve".