665999407 has 2 divisors, whose sum is σ = 665999408. Its totient is φ = 665999406.

The previous prime is 665999377. The next prime is 665999417. The reversal of 665999407 is 704999566.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 665999407 - 2¹¹ = 665997359 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665999417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332999703 + 332999704.

It is an arithmetic number, because the mean of its divisors is an integer number (332999704).

Almost surely, 2^665999407 is an apocalyptic number.

665999407 is a deficient number, since it is larger than the sum of its proper divisors (1).

665999407 is an equidigital number, since it uses as much as digits as its factorization.

665999407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3674160, while the sum is 55.

The square root of 665999407 is about 25806.9643119837. The cubic root of 665999407 is about 873.2889149401.

The spelling of 665999407 in words is "six hundred sixty-five million, nine hundred ninety-nine thousand, four hundred seven".