218971913 has 2 divisors, whose sum is σ = 218971914. Its totient is φ = 218971912.

The previous prime is 218971897. The next prime is 218971927. The reversal of 218971913 is 319179812.

It is a happy number.

218971913 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120406729 + 98565184 = 10973^2 + 9928^2 .

It is a cyclic number.

It is not a de Polignac number, because 218971913 - 2⁴ = 218971897 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218974913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109485956 + 109485957.

It is an arithmetic number, because the mean of its divisors is an integer number (109485957).

Almost surely, 2^218971913 is an apocalyptic number.

It is an amenable number.

218971913 is a deficient number, since it is larger than the sum of its proper divisors (1).

218971913 is an equidigital number, since it uses as much as digits as its factorization.

218971913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 41.

The square root of 218971913 is about 14797.6995847328. The cubic root of 218971913 is about 602.7392464795.

The spelling of 218971913 in words is "two hundred eighteen million, nine hundred seventy-one thousand, nine hundred thirteen".