21211210100 has 36 divisors (see below), whose sum is σ = 46065804204. Its totient is φ = 8477575680.

The previous prime is 21211210079. The next prime is 21211210103. The reversal of 21211210100 is 101211212.

It can be written as a sum of positive squares in 6 ways, for example, as 921486736 + 20289723364 = 30356^2 + 142442^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211210103) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37964 + ... + 209436.

Almost surely, 2^21211210100 is an apocalyptic number.

21211210100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211210100 is an abundant number, since it is smaller than the sum of its proper divisors (24854594104).

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

21211210100 is a wasteful number, since it uses less digits than its factorization.

21211210100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172724 (or 172717 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21211210100 its reverse (101211212), we get a palindrome (21312421312).

The spelling of 21211210100 in words is "twenty-one billion, two hundred eleven million, two hundred ten thousand, one hundred".