217918861440 has 1024 divisors, whose sum is σ = 869341593600. Its totient is φ = 45327237120.

The previous prime is 217918861331. The next prime is 217918861451. The reversal of 217918861440 is 44168819712.

217918861440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 804128505 + ... + 804128775.

It is an arithmetic number, because the mean of its divisors is an integer number (848966400).

Almost surely, 2^217918861440 is an apocalyptic number.

217918861440 is a gapful number since it is divisible by the number (20) 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 217918861440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (434670796800).

217918861440 is an abundant number, since it is smaller than the sum of its proper divisors (651422732160).

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

217918861440 is a wasteful number, since it uses less digits than its factorization.

217918861440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433 (or 421 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 51.

The spelling of 217918861440 in words is "two hundred seventeen billion, nine hundred eighteen million, eight hundred sixty-one thousand, four hundred forty".