118218509 has 4 divisors (see below), whose sum is σ = 118257216. Its totient is φ = 118179804.

The previous prime is 118218497. The next prime is 118218511. The reversal of 118218509 is 905812811.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 905812811 = 47 ⋅19272613.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-118218509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (118218109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14339 + ... + 21024.

It is an arithmetic number, because the mean of its divisors is an integer number (29564304).

Almost surely, 2^118218509 is an apocalyptic number.

It is an amenable number.

118218509 is a deficient number, since it is larger than the sum of its proper divisors (38707).

118218509 is an equidigital number, since it uses as much as digits as its factorization.

118218509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38706.

The product of its (nonzero) digits is 5760, while the sum is 35.

The square root of 118218509 is about 10872.8335313294. The cubic root of 118218509 is about 490.7893829152.

It can be divided in two parts, 1182 and 18509, that added together give a palindrome (19691).

The spelling of 118218509 in words is "one hundred eighteen million, two hundred eighteen thousand, five hundred nine".