71639 has 4 divisors (see below), whose sum is σ = 72720. Its totient is φ = 70560.

The previous prime is 71633. The next prime is 71647. The reversal of 71639 is 93617.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93617 = 179 ⋅523.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71639 is a prime.

It is a Duffinian number.

71639 is a modest number, since divided by 639 gives 71 as remainder.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 434 + ... + 575.

It is an arithmetic number, because the mean of its divisors is an integer number (18180).

2⁷¹⁶³⁹ is an apocalyptic number.

71639 is a deficient number, since it is larger than the sum of its proper divisors (1081).

71639 is a wasteful number, since it uses less digits than its factorization.

71639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1080.

The product of its digits is 1134, while the sum is 26.

The square root of 71639 is about 267.6546282058. The cubic root of 71639 is about 41.5320312054.

It can be divided in two parts, 71 and 639, that multiplied together give a square (45369 = 213²).

The spelling of 71639 in words is "seventy-one thousand, six hundred thirty-nine".