1221120208 has 80 divisors (see below), whose sum is σ = 2978666496. Its totient is φ = 471093120.

The previous prime is 1221120193. The next prime is 1221120211. The reversal of 1221120208 is 8020211221.

It is a super-2 number, since 2×1221120208² = 2982269124771926528, which contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 122085 + ... + 131707.

Almost surely, 2^1221120208 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221120208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1489333248).

1221120208 is an abundant number, since it is smaller than the sum of its proper divisors (1757546288).

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

1221120208 is a wasteful number, since it uses less digits than its factorization.

1221120208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9752 (or 9746 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 1221120208 is about 34944.5304446919. The cubic root of 1221120208 is about 1068.8566726033.

Adding to 1221120208 its reverse (8020211221), we get a palindrome (9241331429).

The spelling of 1221120208 in words is "one billion, two hundred twenty-one million, one hundred twenty thousand, two hundred eight".