21120220021212 has 192 divisors, whose sum is σ = 60707955571200. Its totient is φ = 6388382644416.

The previous prime is 21120220021129. The next prime is 21120220021297. The reversal of 21120220021212 is 21212002202112.

It is a happy number.

21120220021212 is a `hidden beast` number, since 211 + 2 + 0 + 220 + 0 + 21 + 212 = 666.

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 polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5135863 + ... + 8283569.

It is an arithmetic number, because the mean of its divisors is an integer number (316187268600).

Almost surely, 2^{21120220021212} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21120220021212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30353977785600).

21120220021212 is an abundant number, since it is smaller than the sum of its proper divisors (39587735549988).

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

21120220021212 is a wasteful number, since it uses less digits than its factorization.

21120220021212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3147804 (or 3147784 counting only the distinct ones).

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

Adding to 21120220021212 its reverse (21212002202112), we get a palindrome (42332222223324).

The spelling of 21120220021212 in words is "twenty-one trillion, one hundred twenty billion, two hundred twenty million, twenty-one thousand, two hundred twelve".