71986 has 4 divisors (see below), whose sum is σ = 107982. Its totient is φ = 35992.

The previous prime is 71983. The next prime is 71987. The reversal of 71986 is 68917.

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

It can be written as a sum of positive squares in only one way, i.e., 47961 + 24025 = 219^2 + 155^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a plaindrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (71983) by changing a digit.

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 as a sum of consecutive naturals, namely, 17995 + ... + 17998.

2⁷¹⁹⁸⁶ is an apocalyptic number.

71986 is a deficient number, since it is larger than the sum of its proper divisors (35996).

71986 is a wasteful number, since it uses less digits than its factorization.

71986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35995.

The product of its digits is 3024, while the sum is 31.

The square root of 71986 is about 268.3020685720. The cubic root of 71986 is about 41.5989798813.

The spelling of 71986 in words is "seventy-one thousand, nine hundred eighty-six".