65691 has 10 divisors (see below), whose sum is σ = 98252. Its totient is φ = 43740.

The previous prime is 65687. The next prime is 65699. The reversal of 65691 is 19656.

65691 is a `hidden beast` number, since 656 + 9 + 1 = 666.

65691 is nontrivially palindromic in base 12.

It is not a de Polignac number, because 65691 - 2² = 65687 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

65691 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (65699) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 325 + ... + 486.

2⁶⁵⁶⁹¹ is an apocalyptic number.

65691 is a deficient number, since it is larger than the sum of its proper divisors (32561).

65691 is an equidigital number, since it uses as much as digits as its factorization.

65691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 823 (or 814 counting only the distinct ones).

The product of its digits is 1620, while the sum is 27.

The square root of 65691 is about 256.3025555862. The cubic root of 65691 is about 40.3492336887.

It can be divided in two parts, 656 and 91, that added together give a palindrome (747).

The spelling of 65691 in words is "sixty-five thousand, six hundred ninety-one".