21210022100 has 72 divisors (see below), whose sum is σ = 46922517600. Its totient is φ = 8319427200.

The previous prime is 21210022081. The next prime is 21210022109. The reversal of 21210022100 is 122001212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210022109) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2479631 + ... + 2488169.

Almost surely, 2^21210022100 is an apocalyptic number.

21210022100 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 21210022100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23461258800).

21210022100 is an abundant number, since it is smaller than the sum of its proper divisors (25712495500).

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

21210022100 is a wasteful number, since it uses less digits than its factorization.

21210022100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9033 (or 9026 counting only the distinct ones).

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

Adding to 21210022100 its reverse (122001212), we get a palindrome (21332023312).

The spelling of 21210022100 in words is "twenty-one billion, two hundred ten million, twenty-two thousand, one hundred".