665307779 has 4 divisors (see below), whose sum is σ = 681534840. Its totient is φ = 649080720.

The previous prime is 665307761. The next prime is 665307787. The reversal of 665307779 is 977703566.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665307779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665307719) 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, 8113469 + ... + 8113550.

It is an arithmetic number, because the mean of its divisors is an integer number (170383710).

Almost surely, 2^665307779 is an apocalyptic number.

665307779 is a deficient number, since it is larger than the sum of its proper divisors (16227061).

665307779 is a wasteful number, since it uses less digits than its factorization.

665307779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16227060.

The product of its (nonzero) digits is 1666980, while the sum is 50.

The square root of 665307779 is about 25793.5608049761. The cubic root of 665307779 is about 872.9865121362.

The spelling of 665307779 in words is "six hundred sixty-five million, three hundred seven thousand, seven hundred seventy-nine".