665719665 has 32 divisors (see below), whose sum is σ = 1175078016. Its totient is φ = 319741440.

The previous prime is 665719619. The next prime is 665719673. The reversal of 665719665 is 566917566.

It is not a de Polignac number, because 665719665 - 2⁶ = 665719601 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 33639 + ... + 49628.

It is an arithmetic number, because the mean of its divisors is an integer number (36721188).

Almost surely, 2^665719665 is an apocalyptic number.

665719665 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

665719665 is a deficient number, since it is larger than the sum of its proper divisors (509358351).

665719665 is a wasteful number, since it uses less digits than its factorization.

665719665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83329.

The product of its digits is 2041200, while the sum is 51.

The square root of 665719665 is about 25801.5438491576. The cubic root of 665719665 is about 873.1666276442.

The spelling of 665719665 in words is "six hundred sixty-five million, seven hundred nineteen thousand, six hundred sixty-five".