218129813 has 4 divisors (see below), whose sum is σ = 237959808. Its totient is φ = 198299820.

The previous prime is 218129809. The next prime is 218129869. The reversal of 218129813 is 318921812.

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.

It is a cyclic number.

It is not a de Polignac number, because 218129813 - 2² = 218129809 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 (218129413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9914981 + ... + 9915002.

It is an arithmetic number, because the mean of its divisors is an integer number (59489952).

Almost surely, 2^218129813 is an apocalyptic number.

It is an amenable number.

218129813 is a deficient number, since it is larger than the sum of its proper divisors (19829995).

218129813 is a wasteful number, since it uses less digits than its factorization.

218129813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19829994.

The product of its digits is 6912, while the sum is 35.

The square root of 218129813 is about 14769.2184288811. The cubic root of 218129813 is about 601.9656027189.

It can be divided in two parts, 218 and 129813, that added together give a palindrome (130031).

The spelling of 218129813 in words is "two hundred eighteen million, one hundred twenty-nine thousand, eight hundred thirteen".