71989 has 4 divisors (see below), whose sum is σ = 72556. Its totient is φ = 71424.

The previous prime is 71987. The next prime is 71993. The reversal of 71989 is 98917.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 27889 + 44100 = 167^2 + 210^2 .

It is a cyclic number.

It is not a de Polignac number, because 71989 - 2¹ = 71987 is a prime.

It is a super-2 number, since 2×71989² = 10364832242, which contains 22 as substring.

It is a Duffinian number.

71989 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71983) 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, 7 + ... + 379.

It is an arithmetic number, because the mean of its divisors is an integer number (18139).

2⁷¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

71989 is a deficient number, since it is larger than the sum of its proper divisors (567).

71989 is a wasteful number, since it uses less digits than its factorization.

71989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 566.

The product of its digits is 4536, while the sum is 34.

The square root of 71989 is about 268.3076592272. The cubic root of 71989 is about 41.5995577492.

It can be divided in two parts, 719 and 89, that added together give a palindrome (808).

The spelling of 71989 in words is "seventy-one thousand, nine hundred eighty-nine".