21211212220000 has 240 divisors, whose sum is σ = 56969282606544. Its totient is φ = 7707392000000.

The previous prime is 21211212219991. The next prime is 21211212220001. The reversal of 21211212220000 is 2221211212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211212220001) by changing a digit.

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 39 ways as a sum of consecutive naturals, for example, 299384580 + ... + 299455420.

Almost surely, 2^{21211212220000} is an apocalyptic number.

21211212220000 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 21211212220000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28484641303272).

21211212220000 is an abundant number, since it is smaller than the sum of its proper divisors (35758070386544).

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

21211212220000 is a wasteful number, since it uses less digits than its factorization.

21211212220000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72243 (or 72220 counting only the distinct ones).

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

Adding to 21211212220000 its reverse (2221211212), we get a palindrome (21213433431212).

It can be divided in two parts, 2121 and 1212220000, that added together give a palindrome (1212222121).

The spelling of 21211212220000 in words is "twenty-one trillion, two hundred eleven billion, two hundred twelve million, two hundred twenty thousand".