21221000210100 has 216 divisors, whose sum is σ = 64810664331168. Its totient is φ = 5360300064000.

The previous prime is 21221000210089. The next prime is 21221000210191. The reversal of 21221000210100 is 101200012212.

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 71 ways as a sum of consecutive naturals, for example, 1153494102 + ... + 1153512498.

Almost surely, 2^{21221000210100} is an apocalyptic number.

21221000210100 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 21221000210100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32405332165584).

21221000210100 is an abundant number, since it is smaller than the sum of its proper divisors (43589664121068).

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

21221000210100 is a wasteful number, since it uses less digits than its factorization.

21221000210100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29103 (or 29077 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21221000210100 its reverse (101200012212), we get a palindrome (21322200222312).

The spelling of 21221000210100 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred ten thousand, one hundred".