21212100000 has 1296 divisors, whose sum is σ = 97006900536. Its totient is φ = 4354560000.

The previous prime is 21212099999. The next prime is 21212100001. The reversal of 21212100000 is 121212.

It is an interprime number because it is at equal distance from previous prime (21212099999) and next prime (21212100001).

It can be written as a sum of positive squares in 12 ways, for example, as 9121778064 + 12090321936 = 95508^2 + 109956^2 .

It is a super-3 number, since 3×21212100000³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212100001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 573299982 + ... + 573300018.

Almost surely, 2^21212100000 is an apocalyptic number.

21212100000 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 21212100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48503450268).

21212100000 is an abundant number, since it is smaller than the sum of its proper divisors (75794800536).

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

21212100000 is a wasteful number, since it uses less digits than its factorization.

21212100000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21212100000 its reverse (121212), we get a palindrome (21212221212).

The spelling of 21212100000 in words is "twenty-one billion, two hundred twelve million, one hundred thousand".