165855871 has 2 divisors, whose sum is σ = 165855872. Its totient is φ = 165855870.

The previous prime is 165855869. The next prime is 165855913. The reversal of 165855871 is 178558561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 165855871 - 2¹ = 165855869 is a prime.

Together with 165855869, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165855821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82927935 + 82927936.

It is an arithmetic number, because the mean of its divisors is an integer number (82927936).

Almost surely, 2^165855871 is an apocalyptic number.

165855871 is a deficient number, since it is larger than the sum of its proper divisors (1).

165855871 is an equidigital number, since it uses as much as digits as its factorization.

165855871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 336000, while the sum is 46.

The square root of 165855871 is about 12878.5042221525. The cubic root of 165855871 is about 549.4273610219.

The spelling of 165855871 in words is "one hundred sixty-five million, eight hundred fifty-five thousand, eight hundred seventy-one".