218637506668816 has 75 divisors (see below), whose sum is σ = 450120678171283. Its totient is φ = 102880194632960.

The previous prime is 218637506668813. The next prime is 218637506668829. The reversal of 218637506668816 is 618866605736812.

The square root of 218637506668816 is 14786396.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 2 ways, for example, as 67854824659216 + 150782682009600 = 8237404^2 + 12279360^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218637506668811) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 17093067381 + ... + 17093080171.

Almost surely, 2^{218637506668816} is an apocalyptic number.

218637506668816 is the 14786396-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218637506668816

218637506668816 is an abundant number, since it is smaller than the sum of its proper divisors (231483171502467).

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

218637506668816 is an frugal number, since it uses more digits than its factorization.

218637506668816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25658 (or 12810 counting only the distinct ones).

The product of its (nonzero) digits is 836075520, while the sum is 73.

The spelling of 218637506668816 in words is "two hundred eighteen trillion, six hundred thirty-seven billion, five hundred six million, six hundred sixty-eight thousand, eight hundred sixteen".