665788865 has 16 divisors (see below), whose sum is σ = 914436480. Its totient is φ = 455863680.

The previous prime is 665788847. The next prime is 665788919. The reversal of 665788865 is 568887566.

665788865 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 665788865 - 2²⁶ = 598680001 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10421 + ... + 37949.

It is an arithmetic number, because the mean of its divisors is an integer number (57152280).

Almost surely, 2^665788865 is an apocalyptic number.

It is an amenable number.

665788865 is a deficient number, since it is larger than the sum of its proper divisors (248647615).

665788865 is a wasteful number, since it uses less digits than its factorization.

665788865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28232.

The product of its digits is 19353600, while the sum is 59.

The square root of 665788865 is about 25802.8848193375. The cubic root of 665788865 is about 873.1968811379.

The spelling of 665788865 in words is "six hundred sixty-five million, seven hundred eighty-eight thousand, eight hundred sixty-five".