165720671 has 4 divisors (see below), whose sum is σ = 165751344. Its totient is φ = 165690000.

The previous prime is 165720623. The next prime is 165720677. The reversal of 165720671 is 176027561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 176027561 = 9829 ⋅17909.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165720671 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 (165720677) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4835 + ... + 18836.

It is an arithmetic number, because the mean of its divisors is an integer number (41437836).

Almost surely, 2^165720671 is an apocalyptic number.

165720671 is a deficient number, since it is larger than the sum of its proper divisors (30673).

165720671 is an equidigital number, since it uses as much as digits as its factorization.

165720671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30672.

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 165720671 is about 12873.2540952162. The cubic root of 165720671 is about 549.2780290103.

The spelling of 165720671 in words is "one hundred sixty-five million, seven hundred twenty thousand, six hundred seventy-one".