164991 has 8 divisors (see below), whose sum is σ = 225280. Its totient is φ = 107352.

The previous prime is 164987. The next prime is 164999. The reversal of 164991 is 199461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 164991 - 2² = 164987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 164991.

It is not an unprimeable number, because it can be changed into a prime (164999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 511 + ... + 768.

It is an arithmetic number, because the mean of its divisors is an integer number (28160).

2¹⁶⁴⁹⁹¹ is an apocalyptic number.

164991 is a deficient number, since it is larger than the sum of its proper divisors (60289).

164991 is a wasteful number, since it uses less digits than its factorization.

164991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1325.

The product of its digits is 1944, while the sum is 30.

The square root of 164991 is about 406.1908418465. The cubic root of 164991 is about 54.8470682686.

The spelling of 164991 in words is "one hundred sixty-four thousand, nine hundred ninety-one".