21221211100 has 36 divisors (see below), whose sum is σ = 47637966600. Its totient is φ = 8195776960.

The previous prime is 21221211097. The next prime is 21221211113. The reversal of 21221211100 is 111212212.

It is a congruent number.

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, 3655930 + ... + 3661729.

It is an arithmetic number, because the mean of its divisors is an integer number (1323276850).

Almost surely, 2^21221211100 is an apocalyptic number.

21221211100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221211100 is an abundant number, since it is smaller than the sum of its proper divisors (26416755500).

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

21221211100 is a wasteful number, since it uses less digits than its factorization.

21221211100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7317702 (or 7317695 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21221211100 its reverse (111212212), we get a palindrome (21332423312).

The spelling of 21221211100 in words is "twenty-one billion, two hundred twenty-one million, two hundred eleven thousand, one hundred".