165555555 has 16 divisors (see below), whose sum is σ = 288969984. Its totient is φ = 80269280.

The previous prime is 165555529. The next prime is 165555601. The reversal of 165555555 is 555555561.

It is not a de Polignac number, because 165555555 - 2⁶ = 165555491 is a prime.

165555555 is a modest number, since divided by 55555 gives 1655 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 501519 + ... + 501848.

It is an arithmetic number, because the mean of its divisors is an integer number (18060624).

Almost surely, 2^165555555 is an apocalyptic number.

165555555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

165555555 is a deficient number, since it is larger than the sum of its proper divisors (123414429).

165555555 is a wasteful number, since it uses less digits than its factorization.

165555555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1003386.

The product of its digits is 468750, while the sum is 42.

The square root of 165555555 is about 12866.8393554905. The cubic root of 165555555 is about 549.0955437709.

It can be divided in two parts, 1 and 65555555, that added together give a palindrome (65555556).

The spelling of 165555555 in words is "one hundred sixty-five million, five hundred fifty-five thousand, five hundred fifty-five".