665673999 has 4 divisors (see below), whose sum is σ = 887565336. Its totient is φ = 443782664.

The previous prime is 665673997. The next prime is 665674001. The reversal of 665673999 is 999376566.

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

It is an interprime number because it is at equal distance from previous prime (665673997) and next prime (665674001).

It is a cyclic number.

It is not a de Polignac number, because 665673999 - 2¹ = 665673997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665673997) 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, 110945664 + ... + 110945669.

It is an arithmetic number, because the mean of its divisors is an integer number (221891334).

Almost surely, 2^665673999 is an apocalyptic number.

665673999 is a deficient number, since it is larger than the sum of its proper divisors (221891337).

665673999 is a wasteful number, since it uses less digits than its factorization.

665673999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221891336.

The product of its digits is 16533720, while the sum is 60.

The square root of 665673999 is about 25800.6588869354. The cubic root of 665673999 is about 873.1466618131.

The spelling of 665673999 in words is "six hundred sixty-five million, six hundred seventy-three thousand, nine hundred ninety-nine".