• 656 can be written using four 4's:

656 has 10 divisors (see below), whose sum is σ = 1302. Its totient is φ = 320.

The previous prime is 653. The next prime is 659.

It is a happy number.

656 is nontrivially palindromic in base 3, base 9 and base 10.

656 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (653) and next prime (659).

It can be written as a sum of positive squares in only one way, i.e., 400 + 256 = 20^2 + 16^2 .

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

656 is an undulating number in base 9 and base 10.

It is a plaindrome in base 12 and base 14.

It is a nialpdrome in base 4.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5 + ... + 36.

It is an amenable number.

656 is a deficient number, since it is larger than the sum of its proper divisors (646).

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

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

The sum of its prime factors is 49 (or 43 counting only the distinct ones).

The product of its digits is 180, while the sum is 17.

The square root of 656 is about 25.6124969497. The cubic root of 656 is about 8.6889629715.

The spelling of 656 in words is "six hundred fifty-six", and thus it is an aban number and an oban number.

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