1656 has 24 divisors (see below), whose sum is σ = 4680. Its totient is φ = 528.

The previous prime is 1637. The next prime is 1657. The reversal of 1656 is 6561.

1656 is nontrivially palindromic in base 7.

1656 is an esthetic number in base 16, because in such base its adjacent digits differ by 1.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an alternating number because its digits alternate between odd and even.

It is a plaindrome in base 16.

It is a nialpdrome in base 12 and base 14.

It is a zygodrome in base 2.

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 1656.

It is not an unprimeable number, because it can be changed into a prime (1657) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 61 + ... + 83.

It is an arithmetic number, because the mean of its divisors is an integer number (195).

2¹⁶⁵⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2340).

1656 is an abundant number, since it is smaller than the sum of its proper divisors (3024).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1656 is a wasteful number, since it uses less digits than its factorization.

1656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35 (or 28 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 1656 is about 40.6939798988. The cubic root of 1656 is about 11.8309633994.

It can be divided in two parts, 165 and 6, that multiplied together give a triangular number (990 = T₄₄).

The spelling of 1656 in words is "one thousand, six hundred fifty-six".