165919 has 4 divisors (see below), whose sum is σ = 178696. Its totient is φ = 153144.

The previous prime is 165901. The next prime is 165931. The reversal of 165919 is 919561.

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 165919 - 2⁵ = 165887 is a prime.

It is a super-2 number, since 2×165919² = 55058229122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165719) 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, 6369 + ... + 6394.

It is an arithmetic number, because the mean of its divisors is an integer number (44674).

2¹⁶⁵⁹¹⁹ is an apocalyptic number.

165919 is a deficient number, since it is larger than the sum of its proper divisors (12777).

165919 is a wasteful number, since it uses less digits than its factorization.

165919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12776.

The product of its digits is 2430, while the sum is 31.

The square root of 165919 is about 407.3315602798. The cubic root of 165919 is about 54.9497060896.

The spelling of 165919 in words is "one hundred sixty-five thousand, nine hundred nineteen".