218969813 has 8 divisors (see below), whose sum is σ = 231241920. Its totient is φ = 206772480.

The previous prime is 218969791. The next prime is 218969921. The reversal of 218969813 is 318969812.

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

It is a cyclic number.

It is not a de Polignac number, because 218969813 - 2¹² = 218965717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218969713) 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, 12620 + ... + 24437.

It is an arithmetic number, because the mean of its divisors is an integer number (28905240).

Almost surely, 2^218969813 is an apocalyptic number.

It is an amenable number.

218969813 is a deficient number, since it is larger than the sum of its proper divisors (12272107).

218969813 is a wasteful number, since it uses less digits than its factorization.

218969813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37387.

The product of its digits is 186624, while the sum is 47.

The square root of 218969813 is about 14797.6286275876. The cubic root of 218969813 is about 602.7373196624.

Subtracting 218969813 from its reverse (318969812), we obtain a palindrome (99999999).

The spelling of 218969813 in words is "two hundred eighteen million, nine hundred sixty-nine thousand, eight hundred thirteen".