665661660519 has 8 divisors (see below), whose sum is σ = 908189552512. Its totient is φ = 433454104440.

The previous prime is 665661660509. The next prime is 665661660563. The reversal of 665661660519 is 915066166566.

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

It is not a de Polignac number, because 665661660519 - 2⁵ = 665661660487 is a prime.

It is a super-2 number, since 2×665661660519² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

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 polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2580083827 + ... + 2580084084.

It is an arithmetic number, because the mean of its divisors is an integer number (113523694064).

Almost surely, 2^665661660519 is an apocalyptic number.

665661660519 is a deficient number, since it is larger than the sum of its proper divisors (242527891993).

665661660519 is a wasteful number, since it uses less digits than its factorization.

665661660519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5160167957.

The product of its (nonzero) digits is 10497600, while the sum is 57.

The spelling of 665661660519 in words is "six hundred sixty-five billion, six hundred sixty-one million, six hundred sixty thousand, five hundred nineteen".