161665055 has 4 divisors (see below), whose sum is σ = 193998072. Its totient is φ = 129332040.

The previous prime is 161665051. The next prime is 161665057. The reversal of 161665055 is 550566161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 550566161 = 499 ⋅1103339.

It is not a de Polignac number, because 161665055 - 2² = 161665051 is a prime.

It is a super-2 number, since 2×161665055² = 52271180016306050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161665051) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 16166501 + ... + 16166510.

It is an arithmetic number, because the mean of its divisors is an integer number (48499518).

Almost surely, 2^161665055 is an apocalyptic number.

161665055 is a deficient number, since it is larger than the sum of its proper divisors (32333017).

161665055 is an equidigital number, since it uses as much as digits as its factorization.

161665055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32333016.

The product of its (nonzero) digits is 27000, while the sum is 35.

The square root of 161665055 is about 12714.7573708663. The cubic root of 161665055 is about 544.7602177242.

The spelling of 161665055 in words is "one hundred sixty-one million, six hundred sixty-five thousand, fifty-five".