165163391 has 4 divisors (see below), whose sum is σ = 172344432. Its totient is φ = 157982352.

The previous prime is 165163351. The next prime is 165163393. The reversal of 165163391 is 193361561.

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

It is a cyclic number.

It is not a de Polignac number, because 165163391 - 2¹⁰ = 165162367 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 (165163393) 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, 3590486 + ... + 3590531.

It is an arithmetic number, because the mean of its divisors is an integer number (43086108).

Almost surely, 2^165163391 is an apocalyptic number.

165163391 is a deficient number, since it is larger than the sum of its proper divisors (7181041).

165163391 is an equidigital number, since it uses as much as digits as its factorization.

165163391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7181040.

The product of its digits is 14580, while the sum is 35.

The square root of 165163391 is about 12851.5909910019. The cubic root of 165163391 is about 548.6616395625.

The spelling of 165163391 in words is "one hundred sixty-five million, one hundred sixty-three thousand, three hundred ninety-one".