165991726606 has 32 divisors (see below), whose sum is σ = 261483621120. Its totient is φ = 78926054400.

The previous prime is 165991726603. The next prime is 165991726631. The reversal of 165991726606 is 606627199561.

It is a happy number.

165991726606 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165991726603) 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 15 ways as a sum of consecutive naturals, for example, 4022430 + ... + 4063486.

It is an arithmetic number, because the mean of its divisors is an integer number (8171363160).

Almost surely, 2^165991726606 is an apocalyptic number.

165991726606 is a deficient number, since it is larger than the sum of its proper divisors (95491894514).

165991726606 is a wasteful number, since it uses less digits than its factorization.

165991726606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42220.

The product of its (nonzero) digits is 7348320, while the sum is 58.

The spelling of 165991726606 in words is "one hundred sixty-five billion, nine hundred ninety-one million, seven hundred twenty-six thousand, six hundred six".