1211211211100 has 144 divisors (see below), whose sum is σ = 3100526553600. Its totient is φ = 405712051200.

The previous prime is 1211211211097. The next prime is 1211211211129. The reversal of 1211211211100 is 11121121121.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 189851 + ... + 1567949.

It is an arithmetic number, because the mean of its divisors is an integer number (21531434400).

Almost surely, 2^{1211211211100} is an apocalyptic number.

1211211211100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1211211211100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1550263276800).

1211211211100 is an abundant number, since it is smaller than the sum of its proper divisors (1889315342500).

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

1211211211100 is a wasteful number, since it uses less digits than its factorization.

1211211211100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1378188 (or 1378181 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 1211211211100 its reverse (11121121121), we get a palindrome (1222332332221).

The spelling of 1211211211100 in words is "one trillion, two hundred eleven billion, two hundred eleven million, two hundred eleven thousand, one hundred".