21222012100 has 18 divisors (see below), whose sum is σ = 46051766474. Its totient is φ = 8488804800.

The previous prime is 21222012061. The next prime is 21222012107. The reversal of 21222012100 is 121022212.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 5037592576 + 16184419524 = 70976^2 + 127218^2 .

It is not an unprimeable number, because it can be changed into a prime (21222012107) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 106109961 + ... + 106110160.

Almost surely, 2^21222012100 is an apocalyptic number.

21222012100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222012100 is an abundant number, since it is smaller than the sum of its proper divisors (24829754374).

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

21222012100 is a wasteful number, since it uses less digits than its factorization.

21222012100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212220135 (or 212220128 counting only the distinct ones).

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

Adding to 21222012100 its reverse (121022212), we get a palindrome (21343034312).

The spelling of 21222012100 in words is "twenty-one billion, two hundred twenty-two million, twelve thousand, one hundred".