665889279 has 16 divisors (see below), whose sum is σ = 989176320. Its totient is φ = 394981760.

The previous prime is 665889277. The next prime is 665889299. The reversal of 665889279 is 972988566.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 665889279 - 2¹ = 665889277 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665889277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 213114 + ... + 216215.

It is an arithmetic number, because the mean of its divisors is an integer number (61823520).

Almost surely, 2^665889279 is an apocalyptic number.

665889279 is a deficient number, since it is larger than the sum of its proper divisors (323287041).

665889279 is a wasteful number, since it uses less digits than its factorization.

665889279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429390.

The product of its digits is 13063680, while the sum is 60.

The square root of 665889279 is about 25804.8305361612. The cubic root of 665889279 is about 873.2407773281.

The spelling of 665889279 in words is "six hundred sixty-five million, eight hundred eighty-nine thousand, two hundred seventy-nine".