165707066821 has 4 divisors (see below), whose sum is σ = 165714407712. Its totient is φ = 165699725932.

The previous prime is 165707066809. The next prime is 165707066851. The reversal of 165707066821 is 128660707561.

It is a happy number.

165707066821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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-165707066821 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165707066851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3636481 + ... + 3681766.

It is an arithmetic number, because the mean of its divisors is an integer number (41428601928).

Almost surely, 2^165707066821 is an apocalyptic number.

It is an amenable number.

165707066821 is a deficient number, since it is larger than the sum of its proper divisors (7340891).

165707066821 is an equidigital number, since it uses as much as digits as its factorization.

165707066821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7340890.

The product of its (nonzero) digits is 846720, while the sum is 49.

The spelling of 165707066821 in words is "one hundred sixty-five billion, seven hundred seven million, sixty-six thousand, eight hundred twenty-one".