165699996561 has 24 divisors (see below), whose sum is σ = 261830387520. Its totient is φ = 100144485600.

The previous prime is 165699996551. The next prime is 165699996613.

165699996561 is a `hidden beast` number, since 1 + 6 + 56 + 9 + 9 + 9 + 9 + 6 + 561 = 666.

165699996561 is nontrivially palindromic in base 10.

165699996561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 165699996561 - 2¹¹ = 165699994513 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165699996561.

It is not an unprimeable number, because it can be changed into a prime (165699996521) 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 23 ways as a sum of consecutive naturals, for example, 2295570 + ... + 2366651.

It is an arithmetic number, because the mean of its divisors is an integer number (10909599480).

Almost surely, 2^165699996561 is an apocalyptic number.

165699996561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165699996561 is a deficient number, since it is larger than the sum of its proper divisors (96130390959).

165699996561 is a wasteful number, since it uses less digits than its factorization.

165699996561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4662597 (or 4662594 counting only the distinct ones).

The product of its digits is 212576400, while the sum is 72.

The spelling of 165699996561 in words is "one hundred sixty-five billion, six hundred ninety-nine million, nine hundred ninety-six thousand, five hundred sixty-one".