21201110100 has 360 divisors, whose sum is σ = 72733990560. Its totient is φ = 5327182080.

The previous prime is 21201110083. The next prime is 21201110111. The reversal of 21201110100 is 101110212.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

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 119 ways as a sum of consecutive naturals, for example, 53403102 + ... + 53403498.

Almost surely, 2^21201110100 is an apocalyptic number.

21201110100 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 21201110100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36366995280).

21201110100 is an abundant number, since it is smaller than the sum of its proper divisors (51532880460).

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

21201110100 is a wasteful number, since it uses less digits than its factorization.

21201110100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 789 (or 773 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21201110100 its reverse (101110212), we get a palindrome (21302220312).

It can be divided in two parts, 212011 and 10100, that added together give a triangular number (222111 = T₆₆₆).

The spelling of 21201110100 in words is "twenty-one billion, two hundred one million, one hundred ten thousand, one hundred".