165611710222221 has 32 divisors (see below), whose sum is σ = 226181765601792. Its totient is φ = 107729994980160.

The previous prime is 165611710222171. The next prime is 165611710222229. The reversal of 165611710222221 is 122222017116561.

It is not a de Polignac number, because 165611710222221 - 2⁶ = 165611710222157 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165611710222221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165611710222229) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2042455546 + ... + 2042536628.

It is an arithmetic number, because the mean of its divisors is an integer number (7068180175056).

Almost surely, 2^{165611710222221} is an apocalyptic number.

It is an amenable number.

165611710222221 is a deficient number, since it is larger than the sum of its proper divisors (60570055379571).

165611710222221 is a wasteful number, since it uses less digits than its factorization.

165611710222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97113.

The product of its (nonzero) digits is 40320, while the sum is 39.

Adding to 165611710222221 its reverse (122222017116561), we get a palindrome (287833727338782).

The spelling of 165611710222221 in words is "one hundred sixty-five trillion, six hundred eleven billion, seven hundred ten million, two hundred twenty-two thousand, two hundred twenty-one".