1216555200 has 588 divisors, whose sum is σ = 5163769200. Its totient is φ = 276203520.

The previous prime is 1216555189. The next prime is 1216555229. The reversal of 1216555200 is 25556121.

1216555200 is a `hidden beast` number, since 1 + 2 + 1 + 655 + 5 + 2 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 8164726 + ... + 8164874.

Almost surely, 2^1216555200 is an apocalyptic number.

1216555200 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 1216555200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2581884600).

1216555200 is an abundant number, since it is smaller than the sum of its proper divisors (3947214000).

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

1216555200 is an equidigital number, since it uses as much as digits as its factorization.

1216555200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196 (or 166 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The square root of 1216555200 is about 34879.1513658231. The cubic root of 1216555200 is about 1067.5230795742.

The spelling of 1216555200 in words is "one billion, two hundred sixteen million, five hundred fifty-five thousand, two hundred".