21212010100 has 144 divisors (see below), whose sum is σ = 50155289856. Its totient is φ = 7755264000.

The previous prime is 21212010097. The next prime is 21212010119. The reversal of 21212010100 is 101021212.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 18888139 + ... + 18889261.

It is an arithmetic number, because the mean of its divisors is an integer number (348300624).

Almost surely, 2^21212010100 is an apocalyptic number.

21212010100 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 21212010100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25077644928).

21212010100 is an abundant number, since it is smaller than the sum of its proper divisors (28943279756).

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

21212010100 is a wasteful number, since it uses less digits than its factorization.

21212010100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1466 (or 1459 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21212010100 its reverse (101021212), we get a palindrome (21313031312).

The spelling of 21212010100 in words is "twenty-one billion, two hundred twelve million, ten thousand, one hundred".