21200220121212 has 144 divisors (see below), whose sum is σ = 61914196247904. Its totient is φ = 6045032448000.

The previous prime is 21200220121189. The next prime is 21200220121271. The reversal of 21200220121212 is 21212102200212.

It is a happy number.

21200220121212 is a `hidden beast` number, since 21 + 200 + 220 + 1 + 212 + 12 = 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 47 ways as a sum of consecutive naturals, for example, 29406012 + ... + 30118332.

It is an arithmetic number, because the mean of its divisors is an integer number (429959696166).

Almost surely, 2^{21200220121212} is an apocalyptic number.

21200220121212 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 21200220121212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30957098123952).

21200220121212 is an abundant number, since it is smaller than the sum of its proper divisors (40713976126692).

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

21200220121212 is a wasteful number, since it uses less digits than its factorization.

21200220121212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716780 (or 716775 counting only the distinct ones).

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

Adding to 21200220121212 its reverse (21212102200212), we get a palindrome (42412322321424).

The spelling of 21200220121212 in words is "twenty-one trillion, two hundred billion, two hundred twenty million, one hundred twenty-one thousand, two hundred twelve".