666513979 has 2 divisors, whose sum is σ = 666513980. Its totient is φ = 666513978.

The previous prime is 666513949. The next prime is 666513997. The reversal of 666513979 is 979315666.

Together with next prime (666513997) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666513979 - 2⁷ = 666513851 is a prime.

It is not a weakly prime, because it can be changed into another prime (666513929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333256989 + 333256990.

It is an arithmetic number, because the mean of its divisors is an integer number (333256990).

Almost surely, 2^666513979 is an apocalyptic number.

666513979 is a deficient number, since it is larger than the sum of its proper divisors (1).

666513979 is an equidigital number, since it uses as much as digits as its factorization.

666513979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1837080, while the sum is 52.

The square root of 666513979 is about 25816.9320214467. The cubic root of 666513979 is about 873.5137671627.

The spelling of 666513979 in words is "six hundred sixty-six million, five hundred thirteen thousand, nine hundred seventy-nine".