165987 has 6 divisors (see below), whose sum is σ = 239772. Its totient is φ = 110652.

The previous prime is 165983. The next prime is 166013. The reversal of 165987 is 789561.

It is not a de Polignac number, because 165987 - 2² = 165983 is a prime.

165987 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (165983) by changing a digit.

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 in 5 ways as a sum of consecutive naturals, for example, 9213 + ... + 9230.

It is an arithmetic number, because the mean of its divisors is an integer number (39962).

2¹⁶⁵⁹⁸⁷ is an apocalyptic number.

165987 is a deficient number, since it is larger than the sum of its proper divisors (73785).

165987 is a wasteful number, since it uses less digits than its factorization.

165987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18449 (or 18446 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 165987 is about 407.4150218144. The cubic root of 165987 is about 54.9572119000.

The spelling of 165987 in words is "one hundred sixty-five thousand, nine hundred eighty-seven".