1211102100 has 216 divisors, whose sum is σ = 4329332280. Its totient is φ = 280535040.

The previous prime is 1211102069. The next prime is 1211102129. The reversal of 1211102100 is 12011121.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 535829904 + 675272196 = 23148^2 + 25986^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 195856 + ... + 201944.

It is an arithmetic number, because the mean of its divisors is an integer number (20043205).

Almost surely, 2^1211102100 is an apocalyptic number.

1211102100 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 1211102100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2164666140).

1211102100 is an abundant number, since it is smaller than the sum of its proper divisors (3118230180).

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

1211102100 is a wasteful number, since it uses less digits than its factorization.

1211102100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6139 (or 6129 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 1211102100 is about 34800.8922299415. The cubic root of 1211102100 is about 1065.9256648237.

Adding to 1211102100 its reverse (12011121), we get a palindrome (1223113221).

The spelling of 1211102100 in words is "one billion, two hundred eleven million, one hundred two thousand, one hundred".