218640946193 has 4 divisors (see below), whose sum is σ = 231502178340. Its totient is φ = 205779714048.

The previous prime is 218640946187. The next prime is 218640946211. The reversal of 218640946193 is 391649046812.

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

It can be written as a sum of positive squares in 2 ways, for example, as 134466689809 + 84174256384 = 366697^2 + 290128^2 .

It is a cyclic number.

It is not a de Polignac number, because 218640946193 - 2⁶ = 218640946129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218640936193) 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, 6430616048 + ... + 6430616081.

It is an arithmetic number, because the mean of its divisors is an integer number (57875544585).

Almost surely, 2^218640946193 is an apocalyptic number.

It is an amenable number.

218640946193 is a deficient number, since it is larger than the sum of its proper divisors (12861232147).

218640946193 is a wasteful number, since it uses less digits than its factorization.

218640946193 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12861232146.

The product of its (nonzero) digits is 2239488, while the sum is 53.

The spelling of 218640946193 in words is "two hundred eighteen billion, six hundred forty million, nine hundred forty-six thousand, one hundred ninety-three".