218851681218007 has 4 divisors (see below), whose sum is σ = 219374000266680. Its totient is φ = 218329362169336.

The previous prime is 218851681217941. The next prime is 218851681218019. The reversal of 218851681218007 is 700812186158812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218851681218007 is a prime.

It is a super-2 number, since 2×218851681218007² (a number of 29 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218851681218097) 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, 261159523708 + ... + 261159524545.

It is an arithmetic number, because the mean of its divisors is an integer number (54843500066670).

Almost surely, 2^{218851681218007} is an apocalyptic number.

218851681218007 is a deficient number, since it is larger than the sum of its proper divisors (522319048673).

218851681218007 is an equidigital number, since it uses as much as digits as its factorization.

218851681218007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 522319048672.

The product of its (nonzero) digits is 3440640, while the sum is 58.

The spelling of 218851681218007 in words is "two hundred eighteen trillion, eight hundred fifty-one billion, six hundred eighty-one million, two hundred eighteen thousand, seven".