1221211200 has 336 divisors, whose sum is σ = 4433376960. Its totient is φ = 291840000.

The previous prime is 1221211181. The next prime is 1221211231. The reversal of 1221211200 is 21121221.

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 polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5332686 + ... + 5332914.

Almost surely, 2^1221211200 is an apocalyptic number.

1221211200 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 1221211200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2216688480).

1221211200 is an abundant number, since it is smaller than the sum of its proper divisors (3212165760).

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

1221211200 is a wasteful number, since it uses less digits than its factorization.

1221211200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366 (or 351 counting only the distinct ones).

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

The square root of 1221211200 is about 34945.8323695401. The cubic root of 1221211200 is about 1068.8832206286.

Adding to 1221211200 its reverse (21121221), we get a palindrome (1242332421).

It can be divided in two parts, 122121 and 1200, that added together give a palindrome (123321).

The spelling of 1221211200 in words is "one billion, two hundred twenty-one million, two hundred eleven thousand, two hundred".