218187878897 has 2 divisors, whose sum is σ = 218187878898. Its totient is φ = 218187878896.

The previous prime is 218187878893. The next prime is 218187878933. The reversal of 218187878897 is 798878781812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 172689282481 + 45498596416 = 415559^2 + 213304^2 .

It is a cyclic number.

It is not a de Polignac number, because 218187878897 - 2² = 218187878893 is a prime.

It is a super-3 number, since 3×218187878897³ (a number of 35 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (218187878893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109093939448 + 109093939449.

It is an arithmetic number, because the mean of its divisors is an integer number (109093939449).

Almost surely, 2^218187878897 is an apocalyptic number.

It is an amenable number.

218187878897 is a deficient number, since it is larger than the sum of its proper divisors (1).

218187878897 is an equidigital number, since it uses as much as digits as its factorization.

218187878897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 202309632, while the sum is 74.

The spelling of 218187878897 in words is "two hundred eighteen billion, one hundred eighty-seven million, eight hundred seventy-eight thousand, eight hundred ninety-seven".