1215718816 has 72 divisors (see below), whose sum is σ = 2664262692. Its totient is φ = 542822400.

The previous prime is 1215718813. The next prime is 1215718817. The reversal of 1215718816 is 6188175121.

It can be written as a sum of positive squares in 2 ways, for example, as 1196883216 + 18835600 = 34596^2 + 4340^2 .

It is not an unprimeable number, because it can be changed into a prime (1215718811) by changing a digit.

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, 398256 + ... + 401296.

Almost surely, 2^1215718816 is an apocalyptic number.

1215718816 is a gapful number since it is divisible by the number (16) 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 1215718816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1332131346).

1215718816 is an abundant number, since it is smaller than the sum of its proper divisors (1448543876).

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

1215718816 is a wasteful number, since it uses less digits than its factorization.

1215718816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3126 (or 3087 counting only the distinct ones).

The product of its digits is 26880, while the sum is 40.

The square root of 1215718816 is about 34867.1595631190. The cubic root of 1215718816 is about 1067.2783821105.

The spelling of 1215718816 in words is "one billion, two hundred fifteen million, seven hundred eighteen thousand, eight hundred sixteen".