166138465 has 4 divisors (see below), whose sum is σ = 199366164. Its totient is φ = 132910768.

The previous prime is 166138463. The next prime is 166138471. The reversal of 166138465 is 564831661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 564831661 = 6857 ⋅82373.

It can be written as a sum of positive squares in 2 ways, for example, as 24433249 + 141705216 = 4943^2 + 11904^2 .

It is a cyclic number.

It is not a de Polignac number, because 166138465 - 2¹ = 166138463 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166138463) 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, 16613842 + ... + 16613851.

It is an arithmetic number, because the mean of its divisors is an integer number (49841541).

Almost surely, 2^166138465 is an apocalyptic number.

It is an amenable number.

166138465 is a deficient number, since it is larger than the sum of its proper divisors (33227699).

166138465 is an equidigital number, since it uses as much as digits as its factorization.

166138465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33227698.

The product of its digits is 103680, while the sum is 40.

The square root of 166138465 is about 12889.4710907779. The cubic root of 166138465 is about 549.7392317549.

The spelling of 166138465 in words is "one hundred sixty-six million, one hundred thirty-eight thousand, four hundred sixty-five".