218691013 has 2 divisors, whose sum is σ = 218691014. Its totient is φ = 218691012.

The previous prime is 218690981. The next prime is 218691037. The reversal of 218691013 is 310196812.

218691013 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., 140138244 + 78552769 = 11838^2 + 8863^2 .

It is a cyclic number.

It is not a de Polignac number, because 218691013 - 2⁵ = 218690981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218691713) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109345506 + 109345507.

It is an arithmetic number, because the mean of its divisors is an integer number (109345507).

Almost surely, 2^218691013 is an apocalyptic number.

It is an amenable number.

218691013 is a deficient number, since it is larger than the sum of its proper divisors (1).

218691013 is an equidigital number, since it uses as much as digits as its factorization.

218691013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 218691013 is about 14788.2051987386. The cubic root of 218691013 is about 602.4814022943.

The spelling of 218691013 in words is "two hundred eighteen million, six hundred ninety-one thousand, thirteen".