1215555200 has 96 divisors (see below), whose sum is σ = 3033338220. Its totient is φ = 481280000.

The previous prime is 1215555197. The next prime is 1215555217. The reversal of 1215555200 is 25555121.

It can be written as a sum of positive squares in 6 ways, for example, as 756910144 + 458645056 = 27512^2 + 21416^2 .

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 1215555200.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 321320 + ... + 325080.

Almost surely, 2^1215555200 is an apocalyptic number.

1215555200 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 1215555200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1516669110).

1215555200 is an abundant number, since it is smaller than the sum of its proper divisors (1817783020).

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

1215555200 is a wasteful number, since it uses less digits than its factorization.

1215555200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3886 (or 3869 counting only the distinct ones).

The product of its (nonzero) digits is 2500, while the sum is 26.

The square root of 1215555200 is about 34864.8132075880. The cubic root of 1215555200 is about 1067.2305005193.

The spelling of 1215555200 in words is "one billion, two hundred fifteen million, five hundred fifty-five thousand, two hundred".