1211312100 has 36 divisors (see below), whose sum is σ = 3504730544. Its totient is φ = 323016480.

The previous prime is 1211312099. The next prime is 1211312131. The reversal of 1211312100 is 12131121.

It is a Harshad number since it is a multiple of its sum of digits (12).

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, 2018554 + ... + 2019153.

Almost surely, 2^1211312100 is an apocalyptic number.

1211312100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211312100 is an abundant number, since it is smaller than the sum of its proper divisors (2293418444).

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

1211312100 is a wasteful number, since it uses less digits than its factorization.

1211312100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4037724 (or 4037717 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 12.

The square root of 1211312100 is about 34803.9092631848. The cubic root of 1211312100 is about 1065.9872702691.

Adding to 1211312100 its reverse (12131121), we get a palindrome (1223443221).

The spelling of 1211312100 in words is "one billion, two hundred eleven million, three hundred twelve thousand, one hundred".