1211111200 has 144 divisors (see below), whose sum is σ = 3218372136. Its totient is φ = 442368000.

The previous prime is 1211111189. The next prime is 1211111201. The reversal of 1211111200 is 21111121.

It can be written as a sum of positive squares in 12 ways, for example, as 281836944 + 929274256 = 16788^2 + 30484^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (1211111201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1049824 + ... + 1050976.

Almost surely, 2^1211111200 is an apocalyptic number.

1211111200 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 1211111200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1609186068).

1211111200 is an abundant number, since it is smaller than the sum of its proper divisors (2007260936).

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

1211111200 is a wasteful number, since it uses less digits than its factorization.

1211111200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1287 (or 1274 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

The square root of 1211111200 is about 34801.0229734702. The cubic root of 1211111200 is about 1065.9283345406.

Adding to 1211111200 its reverse (21111121), we get a palindrome (1232222321).

The spelling of 1211111200 in words is "one billion, two hundred eleven million, one hundred eleven thousand, two hundred".