665399707 has 4 divisors (see below), whose sum is σ = 760456816. Its totient is φ = 570342600.

The previous prime is 665399687. The next prime is 665399711. The reversal of 665399707 is 707993566.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 665399707 - 2²³ = 657011099 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665399767) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47528544 + ... + 47528557.

It is an arithmetic number, because the mean of its divisors is an integer number (190114204).

Almost surely, 2^665399707 is an apocalyptic number.

665399707 is a deficient number, since it is larger than the sum of its proper divisors (95057109).

665399707 is an equidigital number, since it uses as much as digits as its factorization.

665399707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95057108.

The product of its (nonzero) digits is 2143260, while the sum is 52.

The square root of 665399707 is about 25795.3427385643. The cubic root of 665399707 is about 873.0267181935.

The spelling of 665399707 in words is "six hundred sixty-five million, three hundred ninety-nine thousand, seven hundred seven".