3661 has 4 divisors (see below), whose sum is σ = 4192.
Its totient is φ = 3132.
The previous prime is 3659. The next prime is 3671. The reversal of 3661 is 1663.
It is a happy number.
It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.
It is a cyclic number.
It is not a de Polignac number, because 3661 - 21 = 3659 is a prime.
It is the 61-st Hogben number.
It is a Duffinian number.
3661 is a lucky number.
It is a plaindrome in base 13.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 3661.
It is not an unprimeable number, because it can be changed into a prime (3631) by changing a digit.
It is a nontrivial repunit in base 60.
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 3 ways as a sum of consecutive naturals, for example, 255 + ... + 268.
It is an arithmetic number, because the mean of its divisors is an integer number (1048).
It is an amenable number.
3661 is a deficient number, since it is larger than the sum of its proper divisors (531).
3661 is an equidigital number, since it uses as much as digits as its factorization.
3661 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 530.
The product of its digits is 108, while the sum is 16.
The square root of 3661 is about 60.5061980296.
The cubic root of 3661 is about 15.4122688535.
Subtracting from 3661 its product of digits (108), we obtain a palindrome (3553).
The spelling of 3661 in words is "three thousand, six hundred sixty-one".