21212102000 has 80 divisors (see below), whose sum is σ = 52013617344. Its totient is φ = 8365280000.

The previous prime is 21212101973. The next prime is 21212102003. The reversal of 21212102000 is 20121212.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-3 number, since 3×21212102000³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212102003) 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 15 ways as a sum of consecutive naturals, for example, 67310 + ... + 216690.

Almost surely, 2^21212102000 is an apocalyptic number.

21212102000 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 21212102000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26006808672).

21212102000 is an abundant number, since it is smaller than the sum of its proper divisors (30801515344).

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

21212102000 is a wasteful number, since it uses less digits than its factorization.

21212102000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149475 (or 149459 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21212102000 its reverse (20121212), we get a palindrome (21232223212).

The spelling of 21212102000 in words is "twenty-one billion, two hundred twelve million, one hundred two thousand".