660399707 has 4 divisors (see below), whose sum is σ = 720436056. Its totient is φ = 600363360.

The previous prime is 660399659. The next prime is 660399743. The reversal of 660399707 is 707993066.

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 660399707 - 2¹² = 660395611 is a prime.

It is a super-2 number, since 2×660399707² = 872255546011371698, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660399797) 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, 30018158 + ... + 30018179.

It is an arithmetic number, because the mean of its divisors is an integer number (180109014).

Almost surely, 2^660399707 is an apocalyptic number.

660399707 is a deficient number, since it is larger than the sum of its proper divisors (60036349).

660399707 is a wasteful number, since it uses less digits than its factorization.

660399707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60036348.

The product of its (nonzero) digits is 428652, while the sum is 47.

The square root of 660399707 is about 25698.2432668072. The cubic root of 660399707 is about 870.8344954684.

The spelling of 660399707 in words is "six hundred sixty million, three hundred ninety-nine thousand, seven hundred seven".