518668993 has 2 divisors, whose sum is σ = 518668994. Its totient is φ = 518668992.

The previous prime is 518668907. The next prime is 518669009. The reversal of 518668993 is 399866815.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 363741184 + 154927809 = 19072^2 + 12447^2 .

It is a cyclic number.

It is not a de Polignac number, because 518668993 - 2²⁵ = 485114561 is a prime.

It is not a weakly prime, because it can be changed into another prime (518668903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 259334496 + 259334497.

It is an arithmetic number, because the mean of its divisors is an integer number (259334497).

Almost surely, 2^518668993 is an apocalyptic number.

It is an amenable number.

518668993 is a deficient number, since it is larger than the sum of its proper divisors (1).

518668993 is an equidigital number, since it uses as much as digits as its factorization.

518668993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2799360, while the sum is 55.

The square root of 518668993 is about 22774.3055437482. The cubic root of 518668993 is about 803.4584611175.

The spelling of 518668993 in words is "five hundred eighteen million, six hundred sixty-eight thousand, nine hundred ninety-three".