165994 has 4 divisors (see below), whose sum is σ = 248994. Its totient is φ = 82996.

The previous prime is 165983. The next prime is 166013. The reversal of 165994 is 499561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 499561 = 607 ⋅823.

It can be written as a sum of positive squares in only one way, i.e., 131769 + 34225 = 363^2 + 185^2 .

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41497 + ... + 41500.

2¹⁶⁵⁹⁹⁴ is an apocalyptic number.

165994 is a deficient number, since it is larger than the sum of its proper divisors (83000).

165994 is an equidigital number, since it uses as much as digits as its factorization.

165994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82999.

The product of its digits is 9720, while the sum is 34.

The square root of 165994 is about 407.4236124723. The cubic root of 165994 is about 54.9579844406.

The spelling of 165994 in words is "one hundred sixty-five thousand, nine hundred ninety-four".