218256657817 has 24 divisors (see below), whose sum is σ = 242904916800. Its totient is φ = 194485665600.

The previous prime is 218256657799. The next prime is 218256657841. The reversal of 218256657817 is 718756652812.

It is not a de Polignac number, because 218256657817 - 2¹⁵ = 218256625049 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218256657877) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11983684 + ... + 12001882.

It is an arithmetic number, because the mean of its divisors is an integer number (10121038200).

Almost surely, 2^218256657817 is an apocalyptic number.

It is an amenable number.

218256657817 is a deficient number, since it is larger than the sum of its proper divisors (24648258983).

218256657817 is a wasteful number, since it uses less digits than its factorization.

218256657817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18625 (or 18564 counting only the distinct ones).

The product of its digits is 11289600, while the sum is 58.

The spelling of 218256657817 in words is "two hundred eighteen billion, two hundred fifty-six million, six hundred fifty-seven thousand, eight hundred seventeen".