165511555 has 16 divisors (see below), whose sum is σ = 224143200. Its totient is φ = 116220160.

The previous prime is 165511537. The next prime is 165511571. The reversal of 165511555 is 555115561.

It is not a de Polignac number, because 165511555 - 2⁹ = 165511043 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165511555.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 50290 + ... + 53479.

It is an arithmetic number, because the mean of its divisors is an integer number (14008950).

Almost surely, 2^165511555 is an apocalyptic number.

165511555 is a deficient number, since it is larger than the sum of its proper divisors (58631645).

165511555 is a wasteful number, since it uses less digits than its factorization.

165511555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103814.

The product of its digits is 18750, while the sum is 34.

The square root of 165511555 is about 12865.1294202585. The cubic root of 165511555 is about 549.0468947548.

It can be divided in two parts, 1 and 65511555, that added together give a palindrome (65511556).

The spelling of 165511555 in words is "one hundred sixty-five million, five hundred eleven thousand, five hundred fifty-five".