• 86 can be written using four 4's:

See also 113.

• Sorting the digits of 2⁸⁶ in ascending order we obtain a prime of 26 digits.

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86 has 4 divisors (see below), whose sum is σ = 132. Its totient is φ = 42.

The previous prime is 83. The next prime is 89. The reversal of 86 is 68.

86 = 3² + 4² + ... + 6².

It is a happy number.

86 is nontrivially palindromic in base 6.

86 is an esthetic number in base 5 and base 16, because in such bases its adjacent digits differ by 1.

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

It is an interprime number because it is at equal distance from previous prime (83) and next prime (89).

It is a Curzon number.

86 is a nontrivial repdigit in base 6.

It is a plaindrome in base 4, base 6, base 8, base 11, base 13, base 15 and base 16.

It is a nialpdrome in base 5, base 6, base 10, base 12 and base 14.

It is a zygodrome in base 6.

It is a self number, because there is not a number n which added to its sum of digits gives 86.

It is a congruent number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20 + ... + 23.

It is an arithmetic number, because the mean of its divisors is an integer number (33).

86 is a deficient number, since it is larger than the sum of its proper divisors (46).

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

It is an anagram of its base 13 representation: 86 = (68)₁₃.

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

The sum of its prime factors is 45.

The product of its digits is 48, while the sum is 14.

The square root of 86 is about 9.2736184955. The cubic root of 86 is about 4.4140049624.

Adding to 86 its sum of digits (14), we get a square (100 = 10²).

The spelling of 86 in words is "eighty-six", and thus it is an aban number, an oban number, and an uban number.