391218816 has 192 divisors, whose sum is σ = 1158516000. Its totient is φ = 116508672.

The previous prime is 391218781. The next prime is 391218833. The reversal of 391218816 is 618812193.

It is a tau number, because it is divible by the number of its divisors (192).

Its product of digits (20736) is a multiple of the sum of its prime divisors (96).

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 9098091 + ... + 9098133.

Almost surely, 2^391218816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 391218816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (579258000).

391218816 is an abundant number, since it is smaller than the sum of its proper divisors (767297184).

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

391218816 is a wasteful number, since it uses less digits than its factorization.

391218816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151 (or 96 counting only the distinct ones).

The product of its digits is 20736, while the sum is 39.

The square root of 391218816 is about 19779.2521597759. The cubic root of 391218816 is about 731.3746637632.

The spelling of 391218816 in words is "three hundred ninety-one million, two hundred eighteen thousand, eight hundred sixteen".