1216787328 has 96 divisors (see below), whose sum is σ = 3596191560. Its totient is φ = 394619904.

The previous prime is 1216787321. The next prime is 1216787333. The reversal of 1216787328 is 8237876121.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216787321) 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 11 ways as a sum of consecutive naturals, for example, 28351 + ... + 56897.

Almost surely, 2^1216787328 is an apocalyptic number.

1216787328 is a gapful number since it is divisible by the number (18) 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 1216787328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1798095780).

1216787328 is an abundant number, since it is smaller than the sum of its proper divisors (2379404232).

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

1216787328 is a wasteful number, since it uses less digits than its factorization.

1216787328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28604 (or 28589 counting only the distinct ones).

The product of its digits is 225792, while the sum is 45.

The square root of 1216787328 is about 34882.4788110019. The cubic root of 1216787328 is about 1067.5909724349.

It can be divided in two parts, 1216 and 787328, that added together give a square (788544 = 888²).

The spelling of 1216787328 in words is "one billion, two hundred sixteen million, seven hundred eighty-seven thousand, three hundred twenty-eight".