665661660501 has 8 divisors (see below), whose sum is σ = 887555470464. Its totient is φ = 443771145440.

The previous prime is 665661660497. The next prime is 665661660509. The reversal of 665661660501 is 105066166566.

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 665661660501 - 2² = 665661660497 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665661660509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 305805 + ... + 1193666.

It is an arithmetic number, because the mean of its divisors is an integer number (110944433808).

Almost surely, 2^665661660501 is an apocalyptic number.

It is an amenable number.

665661660501 is a deficient number, since it is larger than the sum of its proper divisors (221893809963).

665661660501 is a wasteful number, since it uses less digits than its factorization.

665661660501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1647451.

The product of its (nonzero) digits is 1166400, while the sum is 48.

The spelling of 665661660501 in words is "six hundred sixty-five billion, six hundred sixty-one million, six hundred sixty thousand, five hundred one".