21222121100 has 36 divisors (see below), whose sum is σ = 47122989144. Its totient is φ = 8291431680.

The previous prime is 21222121097. The next prime is 21222121121. The reversal of 21222121100 is 112122212.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2463389 + ... + 2471988.

Almost surely, 2^21222121100 is an apocalyptic number.

21222121100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222121100 is an abundant number, since it is smaller than the sum of its proper divisors (25900868044).

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

21222121100 is a wasteful number, since it uses less digits than its factorization.

21222121100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4935434 (or 4935427 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21222121100 its reverse (112122212), we get a palindrome (21334243312).

The spelling of 21222121100 in words is "twenty-one billion, two hundred twenty-two million, one hundred twenty-one thousand, one hundred".