218958309 has 12 divisors (see below), whose sum is σ = 327987296. Its totient is φ = 145972044.

The previous prime is 218958293. The next prime is 218958319. The reversal of 218958309 is 903859812.

It is a happy number.

It is not a de Polignac number, because 218958309 - 2⁴ = 218958293 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 (218958319) 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 11 ways as a sum of consecutive naturals, for example, 450289 + ... + 450774.

Almost surely, 2^218958309 is an apocalyptic number.

It is an amenable number.

218958309 is a deficient number, since it is larger than the sum of its proper divisors (109028987).

218958309 is an frugal number, since it uses more digits than its factorization.

218958309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 901078 (or 901066 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The square root of 218958309 is about 14797.2399115511. The cubic root of 218958309 is about 602.7267641564.

The spelling of 218958309 in words is "two hundred eighteen million, nine hundred fifty-eight thousand, three hundred nine".