165255565552561 has 16 divisors (see below), whose sum is σ = 181953619867008. Its totient is φ = 150079500682320.

The previous prime is 165255565552513. The next prime is 165255565552573.

165255565552561 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 165255565552561 - 2⁷ = 165255565552433 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 165255565552493 and 165255565552502.

It is not an unprimeable number, because it can be changed into a prime (165255565552261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61844706 + ... + 64461451.

It is an arithmetic number, because the mean of its divisors is an integer number (11372101241688).

Almost surely, 2^{165255565552561} is an apocalyptic number.

165255565552561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165255565552561 is a deficient number, since it is larger than the sum of its proper divisors (16698054314447).

165255565552561 is an equidigital number, since it uses as much as digits as its factorization.

165255565552561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126307173 (or 126307151 counting only the distinct ones).

The product of its digits is 337500000, while the sum is 64.

The spelling of 165255565552561 in words is "one hundred sixty-five trillion, two hundred fifty-five billion, five hundred sixty-five million, five hundred fifty-two thousand, five hundred sixty-one".