1211221200 has 180 divisors, whose sum is σ = 4513624800. Its totient is φ = 276837120.

The previous prime is 1211221199. The next prime is 1211221213. The reversal of 1211221200 is 21221121.

1211221200 is nontrivially palindromic in base 9.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 48501 + ... + 69099.

Almost surely, 2^1211221200 is an apocalyptic number.

1211221200 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 1211221200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2256812400).

1211221200 is an abundant number, since it is smaller than the sum of its proper divisors (3302403600).

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

1211221200 is a wasteful number, since it uses less digits than its factorization.

1211221200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20634 (or 20616 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1211221200 is about 34802.6033508989. The cubic root of 1211221200 is about 1065.9606047861.

Adding to 1211221200 its reverse (21221121), we get a palindrome (1232442321).

The spelling of 1211221200 in words is "one billion, two hundred eleven million, two hundred twenty-one thousand, two hundred".