1221558800 has 240 divisors, whose sum is σ = 3875859072. Its totient is φ = 358195200.

The previous prime is 1221558799. The next prime is 1221558803. The reversal of 1221558800 is 88551221.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1221558803) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 522434 + ... + 524766.

Almost surely, 2^1221558800 is an apocalyptic number.

1221558800 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 1221558800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1937929536).

1221558800 is an abundant number, since it is smaller than the sum of its proper divisors (2654300272).

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

1221558800 is a wasteful number, since it uses less digits than its factorization.

1221558800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2386 (or 2375 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 32.

The square root of 1221558800 is about 34950.8054270570. The cubic root of 1221558800 is about 1068.9846250271.

The spelling of 1221558800 in words is "one billion, two hundred twenty-one million, five hundred fifty-eight thousand, eight hundred".