165806957 has 4 divisors (see below), whose sum is σ = 165938076. Its totient is φ = 165675840.

The previous prime is 165806923. The next prime is 165806959. The reversal of 165806957 is 759608561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 759608561 = 53 ⋅14332237.

It can be written as a sum of positive squares in 2 ways, for example, as 112063396 + 53743561 = 10586^2 + 7331^2 .

It is a cyclic number.

It is not a de Polignac number, because 165806957 - 2¹⁰ = 165805933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165806959) 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, 63644 + ... + 66197.

It is an arithmetic number, because the mean of its divisors is an integer number (41484519).

Almost surely, 2^165806957 is an apocalyptic number.

It is an amenable number.

165806957 is a deficient number, since it is larger than the sum of its proper divisors (131119).

165806957 is a wasteful number, since it uses less digits than its factorization.

165806957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131118.

The product of its (nonzero) digits is 453600, while the sum is 47.

The square root of 165806957 is about 12876.6050261705. The cubic root of 165806957 is about 549.3733435746.

The spelling of 165806957 in words is "one hundred sixty-five million, eight hundred six thousand, nine hundred fifty-seven".