21201100021212 has 144 divisors (see below), whose sum is σ = 53070655421952. Its totient is φ = 6574875183360.

The previous prime is 21201100021177. The next prime is 21201100021217. The reversal of 21201100021212 is 21212000110212.

It is a junction number, because it is equal to n+sod(n) for n = 21201100021191 and 21201100021200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201100021217) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1410484137 + ... + 1410499167.

It is an arithmetic number, because the mean of its divisors is an integer number (368546218208).

Almost surely, 2^{21201100021212} 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 21201100021212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26535327710976).

21201100021212 is an abundant number, since it is smaller than the sum of its proper divisors (31869555400740).

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

21201100021212 is a wasteful number, since it uses less digits than its factorization.

21201100021212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18868 (or 18829 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21201100021212 its reverse (21212000110212), we get a palindrome (42413100131424).

The spelling of 21201100021212 in words is "twenty-one trillion, two hundred one billion, one hundred million, twenty-one thousand, two hundred twelve".