3649 has 4 divisors (see below), whose sum is σ = 3780. Its totient is φ = 3520.

The previous prime is 3643. The next prime is 3659. The reversal of 3649 is 9463.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 400 + 3249 = 20^2 + 57^2 .

It is a cyclic number.

It is not a de Polignac number, because 3649 - 2⁵ = 3617 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 14 and base 15.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (3643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4 + ... + 85.

It is an arithmetic number, because the mean of its divisors is an integer number (945).

It is a Proth number, since it is equal to 57 ⋅ 2⁶ + 1 and 57 < 2⁶.

2³⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

3649 is a deficient number, since it is larger than the sum of its proper divisors (131).

3649 is an equidigital number, since it uses as much as digits as its factorization.

3649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130.

The product of its digits is 648, while the sum is 22.

The square root of 3649 is about 60.4069532422. The cubic root of 3649 is about 15.3954110125.

It can be divided in two parts, 364 and 9, that added together give a palindrome (373).

The spelling of 3649 in words is "three thousand, six hundred forty-nine".