171639 has 20 divisors (see below), whose sum is σ = 277816. Its totient is φ = 104976.

The previous prime is 171637. The next prime is 171641. The reversal of 171639 is 936171.

It is an interprime number because it is at equal distance from previous prime (171637) and next prime (171641).

It is not a de Polignac number, because 171639 - 2¹ = 171637 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (171637) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 972 + ... + 1134.

2¹⁷¹⁶³⁹ is an apocalyptic number.

171639 is a deficient number, since it is larger than the sum of its proper divisors (106177).

171639 is a wasteful number, since it uses less digits than its factorization.

171639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188 (or 179 counting only the distinct ones).

The product of its digits is 1134, while the sum is 27.

The square root of 171639 is about 414.2933743134. The cubic root of 171639 is about 55.5740428843.

The spelling of 171639 in words is "one hundred seventy-one thousand, six hundred thirty-nine".