218615985 has 24 divisors (see below), whose sum is σ = 433068480. Its totient is φ = 99938592.

The previous prime is 218615953. The next prime is 218615987. The reversal of 218615985 is 589516812.

It is a happy number.

218615985 is a `hidden beast` number, since 21 + 8 + 615 + 9 + 8 + 5 = 666.

It is not a de Polignac number, because 218615985 - 2⁵ = 218615953 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 218615985.

It is not an unprimeable number, because it can be changed into a prime (218615987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 346695 + ... + 347324.

It is an arithmetic number, because the mean of its divisors is an integer number (18044520).

Almost surely, 2^218615985 is an apocalyptic number.

It is an amenable number.

218615985 is a deficient number, since it is larger than the sum of its proper divisors (214452495).

218615985 is a wasteful number, since it uses less digits than its factorization.

218615985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694037 (or 694034 counting only the distinct ones).

The product of its digits is 172800, while the sum is 45.

The square root of 218615985 is about 14785.6682297419. The cubic root of 218615985 is about 602.4124951113.

The spelling of 218615985 in words is "two hundred eighteen million, six hundred fifteen thousand, nine hundred eighty-five".