218392945 has 8 divisors (see below), whose sum is σ = 264476520. Its totient is φ = 173111040.

The previous prime is 218392943. The next prime is 218392963. The reversal of 218392945 is 549293812.

It can be written as a sum of positive squares in 4 ways, for example, as 9388096 + 209004849 = 3064^2 + 14457^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 218392945 - 2¹ = 218392943 is a prime.

It is not an unprimeable number, because it can be changed into a prime (218392943) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 199816 + ... + 200905.

It is an arithmetic number, because the mean of its divisors is an integer number (33059565).

Almost surely, 2^218392945 is an apocalyptic number.

It is an amenable number.

218392945 is a deficient number, since it is larger than the sum of its proper divisors (46083575).

218392945 is a wasteful number, since it uses less digits than its factorization.

218392945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400835.

The product of its digits is 155520, while the sum is 43.

The square root of 218392945 is about 14778.1238660393. The cubic root of 218392945 is about 602.2075576688.

The spelling of 218392945 in words is "two hundred eighteen million, three hundred ninety-two thousand, nine hundred forty-five".