165665554 has 4 divisors (see below), whose sum is σ = 248498334. Its totient is φ = 82832776.

The previous prime is 165665551. The next prime is 165665557. The reversal of 165665554 is 455566561.

165665554 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 455566561 = 17 ⋅26798033.

It is an interprime number because it is at equal distance from previous prime (165665551) and next prime (165665557).

It can be written as a sum of positive squares in only one way, i.e., 137522529 + 28143025 = 11727^2 + 5305^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 165665554.

It is not an unprimeable number, because it can be changed into a prime (165665551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41416387 + ... + 41416390.

Almost surely, 2^165665554 is an apocalyptic number.

165665554 is a deficient number, since it is larger than the sum of its proper divisors (82832780).

165665554 is an equidigital number, since it uses as much as digits as its factorization.

165665554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82832779.

The product of its digits is 540000, while the sum is 43.

The square root of 165665554 is about 12871.1131608731. The cubic root of 165665554 is about 549.2171275068.

The spelling of 165665554 in words is "one hundred sixty-five million, six hundred sixty-five thousand, five hundred fifty-four".