171890639 has 4 divisors (see below), whose sum is σ = 172103400. Its totient is φ = 171677880.

The previous prime is 171890603. The next prime is 171890683. The reversal of 171890639 is 936098171.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-171890639 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 171890639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (171890539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105164 + ... + 106785.

It is an arithmetic number, because the mean of its divisors is an integer number (43025850).

Almost surely, 2^171890639 is an apocalyptic number.

171890639 is a deficient number, since it is larger than the sum of its proper divisors (212761).

171890639 is an equidigital number, since it uses as much as digits as its factorization.

171890639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212760.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 171890639 is about 13110.7070366171. The cubic root of 171890639 is about 556.0118855610.

The spelling of 171890639 in words is "one hundred seventy-one million, eight hundred ninety thousand, six hundred thirty-nine".