666605509939 has 2 divisors, whose sum is σ = 666605509940. Its totient is φ = 666605509938.

The previous prime is 666605509877. The next prime is 666605509961. The reversal of 666605509939 is 939905506666.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666605509939 - 2¹¹ = 666605507891 is a prime.

It is not a weakly prime, because it can be changed into another prime (663605509939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333302754969 + 333302754970.

It is an arithmetic number, because the mean of its divisors is an integer number (333302754970).

Almost surely, 2^666605509939 is an apocalyptic number.

666605509939 is a deficient number, since it is larger than the sum of its proper divisors (1).

666605509939 is an equidigital number, since it uses as much as digits as its factorization.

666605509939 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 70858800, while the sum is 64.

The spelling of 666605509939 in words is "six hundred sixty-six billion, six hundred five million, five hundred nine thousand, nine hundred thirty-nine".