1221009200 has 60 divisors (see below), whose sum is σ = 2962616928. Its totient is φ = 483552000.

The previous prime is 1221009191. The next prime is 1221009203. The reversal of 1221009200 is 29001221.

It is not an unprimeable number, because it can be changed into a prime (1221009203) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25289 + ... + 55511.

Almost surely, 2^1221009200 is an apocalyptic number.

1221009200 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 1221009200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1481308464).

1221009200 is an abundant number, since it is smaller than the sum of its proper divisors (1741607728).

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

1221009200 is a wasteful number, since it uses less digits than its factorization.

1221009200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30342 (or 30331 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 1221009200 is about 34942.9420627399. The cubic root of 1221009200 is about 1068.8242828799.

The spelling of 1221009200 in words is "one billion, two hundred twenty-one million, nine thousand, two hundred".