665759999 has 4 divisors (see below), whose sum is σ = 687236160. Its totient is φ = 644283840.

The previous prime is 665759993. The next prime is 665760023. The reversal of 665759999 is 999957566.

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-665759999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665759993) 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, 10738034 + ... + 10738095.

It is an arithmetic number, because the mean of its divisors is an integer number (171809040).

Almost surely, 2^665759999 is an apocalyptic number.

665759999 is a deficient number, since it is larger than the sum of its proper divisors (21476161).

665759999 is a wasteful number, since it uses less digits than its factorization.

665759999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21476160.

The product of its digits is 41334300, while the sum is 65.

The square root of 665759999 is about 25802.3254572141. The cubic root of 665759999 is about 873.1842614888.

The spelling of 665759999 in words is "six hundred sixty-five million, seven hundred fifty-nine thousand, nine hundred ninety-nine".