665665601 has 8 divisors (see below), whose sum is σ = 671337984. Its totient is φ = 660005280.

The previous prime is 665665597. The next prime is 665665607. The reversal of 665665601 is 106566566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 665665601 - 2² = 665665597 is a prime.

It is a super-2 number, since 2×665665601² = 886221384709382402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665665607) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133316 + ... + 138218.

It is an arithmetic number, because the mean of its divisors is an integer number (83917248).

Almost surely, 2^665665601 is an apocalyptic number.

It is an amenable number.

665665601 is a deficient number, since it is larger than the sum of its proper divisors (5672383).

665665601 is a wasteful number, since it uses less digits than its factorization.

665665601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6031.

The product of its (nonzero) digits is 194400, while the sum is 41.

The square root of 665665601 is about 25800.4961386404. The cubic root of 665665601 is about 873.1429899875.

The spelling of 665665601 in words is "six hundred sixty-five million, six hundred sixty-five thousand, six hundred one".