1647 has 8 divisors (see below), whose sum is σ = 2480. Its totient is φ = 1080.

The previous prime is 1637. The next prime is 1657. The reversal of 1647 is 7461.

1647 is nontrivially palindromic in base 13.

It is an interprime number because it is at equal distance from previous prime (1637) and next prime (1657).

It is not a de Polignac number, because 1647 - 2⁶ = 1583 is a prime.

It is a Duffinian number.

1647 is a nontrivial repdigit in base 13.

It is a plaindrome in base 11, base 13 and base 16.

It is a nialpdrome in base 12 and base 13.

It is a zygodrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1607) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4 + ... + 57.

It is an arithmetic number, because the mean of its divisors is an integer number (310).

1647 is a deficient number, since it is larger than the sum of its proper divisors (833).

1647 is an equidigital number, since it uses as much as digits as its factorization.

1647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70 (or 64 counting only the distinct ones).

The product of its digits is 168, while the sum is 18.

The square root of 1647 is about 40.5832477754. The cubic root of 1647 is about 11.8094915493.

Multiplying 1647 by its sum of digits (18), we get a triangular number (29646 = T₂₄₃).

It can be divided in two parts, 164 and 7, that added together give a palindrome (171).

The spelling of 1647 in words is "one thousand, six hundred forty-seven".