21212220000 has 240 divisors, whose sum is σ = 69848578800. Its totient is φ = 5634816000.

The previous prime is 21212219983. The next prime is 21212220011. The reversal of 21212220000 is 2221212.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 20939494 + ... + 20940506.

It is an arithmetic number, because the mean of its divisors is an integer number (291035745).

Almost surely, 2^21212220000 is an apocalyptic number.

21212220000 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 21212220000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34924289400).

21212220000 is an abundant number, since it is smaller than the sum of its proper divisors (48636358800).

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

21212220000 is a wasteful number, since it uses less digits than its factorization.

21212220000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1395 (or 1372 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21212220000 its reverse (2221212), we get a palindrome (21214441212).

The spelling of 21212220000 in words is "twenty-one billion, two hundred twelve million, two hundred twenty thousand".