665661161606 has 64 divisors (see below), whose sum is σ = 1237546252800. Its totient is φ = 262067249664.

The previous prime is 665661161597. The next prime is 665661161629. The reversal of 665661161606 is 606161166566.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1546625 + ... + 1929603.

It is an arithmetic number, because the mean of its divisors is an integer number (19336660200).

Almost surely, 2^665661161606 is an apocalyptic number.

665661161606 is a deficient number, since it is larger than the sum of its proper divisors (571885091194).

665661161606 is a wasteful number, since it uses less digits than its factorization.

665661161606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383181.

The product of its (nonzero) digits is 1399680, while the sum is 50.

The spelling of 665661161606 in words is "six hundred sixty-five billion, six hundred sixty-one million, one hundred sixty-one thousand, six hundred six".