165998 has 16 divisors (see below), whose sum is σ = 290304. Its totient is φ = 69720.

The previous prime is 165983. The next prime is 166013. The reversal of 165998 is 899561.

It is an interprime number because it is at equal distance from previous prime (165983) and next prime (166013).

It is a Curzon 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 165998.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 911 + ... + 1077.

It is an arithmetic number, because the mean of its divisors is an integer number (18144).

2¹⁶⁵⁹⁹⁸ is an apocalyptic number.

165998 is a deficient number, since it is larger than the sum of its proper divisors (124306).

165998 is a wasteful number, since it uses less digits than its factorization.

165998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247.

The product of its digits is 19440, while the sum is 38.

The square root of 165998 is about 407.4285213384. The cubic root of 165998 is about 54.9584258826.

The spelling of 165998 in words is "one hundred sixty-five thousand, nine hundred ninety-eight".