165638 has 8 divisors (see below), whose sum is σ = 271080. Its totient is φ = 75280.

The previous prime is 165617. The next prime is 165653. The reversal of 165638 is 836561.

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

It is a super-3 number, since 3×165638³ = 13633306189422216, which contains 333 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 165638.

It is a congruent number.

It is an unprimeable number.

165638 is an untouchable number, because it is not equal to the sum of proper divisors of any 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 in 3 ways as a sum of consecutive naturals, for example, 3743 + ... + 3786.

It is an arithmetic number, because the mean of its divisors is an integer number (33885).

2¹⁶⁵⁶³⁸ is an apocalyptic number.

165638 is a deficient number, since it is larger than the sum of its proper divisors (105442).

165638 is a wasteful number, since it uses less digits than its factorization.

165638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7542.

The product of its digits is 4320, while the sum is 29.

The square root of 165638 is about 406.9864862621. The cubic root of 165638 is about 54.9186676663.

The spelling of 165638 in words is "one hundred sixty-five thousand, six hundred thirty-eight".