165603645605 has 4 divisors (see below), whose sum is σ = 198724374732. Its totient is φ = 132482916480.

The previous prime is 165603645583. The next prime is 165603645721. The reversal of 165603645605 is 506546306561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 99664595809 + 65939049796 = 315697^2 + 256786^2 .

It is not a de Polignac number, because 165603645605 - 2⁶ = 165603645541 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 165603645605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16560364556 + ... + 16560364565.

It is an arithmetic number, because the mean of its divisors is an integer number (49681093683).

Almost surely, 2^165603645605 is an apocalyptic number.

It is an amenable number.

165603645605 is a deficient number, since it is larger than the sum of its proper divisors (33120729127).

165603645605 is an equidigital number, since it uses as much as digits as its factorization.

165603645605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33120729126.

The product of its (nonzero) digits is 1944000, while the sum is 47.

The spelling of 165603645605 in words is "one hundred sixty-five billion, six hundred three million, six hundred forty-five thousand, six hundred five".