165138749 has 4 divisors (see below), whose sum is σ = 165197340. Its totient is φ = 165080160.

The previous prime is 165138739. The next prime is 165138763. The reversal of 165138749 is 947831561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4305625 + 160833124 = 2075^2 + 12682^2 .

It is a cyclic number.

It is not a de Polignac number, because 165138749 - 2¹² = 165134653 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165138739) 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 in 3 ways as a sum of consecutive naturals, for example, 24842 + ... + 30779.

It is an arithmetic number, because the mean of its divisors is an integer number (41299335).

Almost surely, 2^165138749 is an apocalyptic number.

It is an amenable number.

165138749 is a deficient number, since it is larger than the sum of its proper divisors (58591).

165138749 is an equidigital number, since it uses as much as digits as its factorization.

165138749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58590.

The product of its digits is 181440, while the sum is 44.

The square root of 165138749 is about 12850.6322412557. The cubic root of 165138749 is about 548.6343518517.

The spelling of 165138749 in words is "one hundred sixty-five million, one hundred thirty-eight thousand, seven hundred forty-nine".