1211111212100 has 18 divisors (see below), whose sum is σ = 2628111330474. Its totient is φ = 484444484800.

The previous prime is 1211111212079. The next prime is 1211111212109. The reversal of 1211111212100 is 12121111121.

It can be written as a sum of positive squares in 3 ways, for example, as 48125829376 + 1162985382724 = 219376^2 + 1078418^2 .

It is not an unprimeable number, because it can be changed into a prime (1211111212109) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6055555961 + ... + 6055556160.

Almost surely, 2^{1211111212100} is an apocalyptic number.

1211111212100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211111212100 is an abundant number, since it is smaller than the sum of its proper divisors (1417000118374).

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

1211111212100 is a wasteful number, since it uses less digits than its factorization.

1211111212100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12111112135 (or 12111112128 counting only the distinct ones).

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

Adding to 1211111212100 its reverse (12121111121), we get a palindrome (1223232323221).

The spelling of 1211111212100 in words is "one trillion, two hundred eleven billion, one hundred eleven million, two hundred twelve thousand, one hundred".