21220212100 has 36 divisors (see below), whose sum is σ = 46179878500. Its totient is φ = 8463749760.

The previous prime is 21220212067. The next prime is 21220212157. The reversal of 21220212100 is 121202212.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 958397764 + 20261814336 = 30958^2 + 142344^2 .

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 11 ways as a sum of consecutive naturals, for example, 269115 + ... + 338914.

Almost surely, 2^21220212100 is an apocalyptic number.

21220212100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21220212100 is an abundant number, since it is smaller than the sum of its proper divisors (24959666400).

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

21220212100 is a wasteful number, since it uses less digits than its factorization.

21220212100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608392 (or 608385 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21220212100 its reverse (121202212), we get a palindrome (21341414312).

The spelling of 21220212100 in words is "twenty-one billion, two hundred twenty million, two hundred twelve thousand, one hundred".