666658879 has 2 divisors, whose sum is σ = 666658880. Its totient is φ = 666658878.

The previous prime is 666658793. The next prime is 666658897. The reversal of 666658879 is 978856666.

Together with next prime (666658897) 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 666658879 - 2¹³ = 666650687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666658079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333329439 + 333329440.

It is an arithmetic number, because the mean of its divisors is an integer number (333329440).

Almost surely, 2^666658879 is an apocalyptic number.

666658879 is a deficient number, since it is larger than the sum of its proper divisors (1).

666658879 is an equidigital number, since it uses as much as digits as its factorization.

666658879 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26127360, while the sum is 61.

The square root of 666658879 is about 25819.7381667592. The cubic root of 666658879 is about 873.5770631463.

The spelling of 666658879 in words is "six hundred sixty-six million, six hundred fifty-eight thousand, eight hundred seventy-nine".