1216817280 has 384 divisors, whose sum is σ = 4865253120. Its totient is φ = 274489344.

The previous prime is 1216817269. The next prime is 1216817281. The reversal of 1216817280 is 827186121.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (1216817281) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4152814 + ... + 4153106.

It is an arithmetic number, because the mean of its divisors is an integer number (12669930).

Almost surely, 2^1216817280 is an apocalyptic number.

1216817280 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 1216817280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2432626560).

1216817280 is an abundant number, since it is smaller than the sum of its proper divisors (3648435840).

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

1216817280 is a wasteful number, since it uses less digits than its factorization.

1216817280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428 (or 413 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The square root of 1216817280 is about 34882.9081356472. The cubic root of 1216817280 is about 1067.5997321751.

The spelling of 1216817280 in words is "one billion, two hundred sixteen million, eight hundred seventeen thousand, two hundred eighty".