2644 has 6 divisors (see below), whose sum is σ = 4634.
Its totient is φ = 1320.
The previous prime is 2633. The next prime is 2647. The reversal of 2644 is 4462.
Subtracting from 2644 its sum of digits (16), we obtain a triangular number (2628 = T72).
It can be divided in two parts, 2 and 644, that added together give a palindrome (646).
It can be written as a sum of positive squares in only one way, i.e., 2500 + 144 = 50^2 + 12^2
It is a plaindrome in base 9.
It is a nialpdrome in base 4, base 15 and base 16.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (2647) 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 as a sum of consecutive naturals, namely, 327 + ... + 334.
22644 is an apocalyptic number.
It is an amenable number.
2644 is a deficient number, since it is larger than the sum of its proper divisors (1990).
2644 is a wasteful number, since it uses less digits than its factorization.
2644 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 665 (or 663 counting only the distinct ones).
The product of its digits is 192, while the sum is 16.
The square root of 2644 is about 51.4198405287.
The cubic root of 2644 is about 13.8278231631.
The spelling of 2644 in words is "two thousand, six hundred forty-four".