165105635921 has 4 divisors (see below), whose sum is σ = 165230057472. Its totient is φ = 164981214372.

The previous prime is 165105635897. The next prime is 165105636011. The reversal of 165105635921 is 129536501561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165105635921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165105635021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62208785 + ... + 62211438.

It is an arithmetic number, because the mean of its divisors is an integer number (41307514368).

Almost surely, 2^165105635921 is an apocalyptic number.

It is an amenable number.

165105635921 is a deficient number, since it is larger than the sum of its proper divisors (124421551).

165105635921 is a wasteful number, since it uses less digits than its factorization.

165105635921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124421550.

The product of its (nonzero) digits is 243000, while the sum is 44.

The spelling of 165105635921 in words is "one hundred sixty-five billion, one hundred five million, six hundred thirty-five thousand, nine hundred twenty-one".