218365551616 has 99 divisors (see below), whose sum is σ = 464246267889. Its totient is φ = 102640631808.

The previous prime is 218365551587. The next prime is 218365551641. The reversal of 218365551616 is 616155563812.

It is a happy number.

The square root of 218365551616 is 467296.

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

It can be written as a sum of positive squares in only one way, i.e., 170007782400 + 48357769216 = 412320^2 + 219904^2 .

It is a super-2 number, since 2×218365551616² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 218365551616.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 254208595 + ... + 254209453.

Almost surely, 2^218365551616 is an apocalyptic number.

218365551616 is the 467296-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218365551616

218365551616 is an abundant number, since it is smaller than the sum of its proper divisors (245880716273).

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

218365551616 is an frugal number, since it uses more digits than its factorization.

218365551616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1772 (or 878 counting only the distinct ones).

The product of its digits is 1296000, while the sum is 49.

Multiplying 218365551616 by its sum of digits (49), we get a square (10699912029184 = 3271072²).

The spelling of 218365551616 in words is "two hundred eighteen billion, three hundred sixty-five million, five hundred fifty-one thousand, six hundred sixteen".