86661 has 6 divisors (see below), whose sum is σ = 125190. Its totient is φ = 57768.

The previous prime is 86629. The next prime is 86677. The reversal of 86661 is 16668.

It can be written as a sum of positive squares in only one way, i.e., 86436 + 225 = 294^2 + 15^2 .

It is not a de Polignac number, because 86661 - 2⁵ = 86629 is a prime.

86661 is a lucky number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (86161) 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 in 5 ways as a sum of consecutive naturals, for example, 4806 + ... + 4823.

It is an arithmetic number, because the mean of its divisors is an integer number (20865).

2⁸⁶⁶⁶¹ is an apocalyptic number.

It is an amenable number.

86661 is a deficient number, since it is larger than the sum of its proper divisors (38529).

86661 is a wasteful number, since it uses less digits than its factorization.

86661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9635 (or 9632 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 86661 is about 294.3824043655. The cubic root of 86661 is about 44.2528486149.

It can be divided in two parts, 86 and 661, that added together give a palindrome (747).

The spelling of 86661 in words is "eighty-six thousand, six hundred sixty-one".