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856 = 23107

856 has 8 divisors (see below), whose sum is σ = 1620. Its totient is φ = 424.

The previous prime is 853. The next prime is 857. The reversal of 856 is 658.

856 is nontrivially palindromic in base 5 and base 7.

856 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (8).

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

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (853) 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, 46 + ... + 61.

856 is the 16-th nonagonal number.

856 is the 19-th centered pentagonal number.

It is an amenable number.

856 is a deficient number, since it is larger than the sum of its proper divisors (764).

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

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

The sum of its prime factors is 113 (or 109 counting only the distinct ones).

The product of its digits is 240, while the sum is 19.

The square root of 856 is about 29.2574776767. The cubic root of 856 is about 9.4949187970.

Subtracting from 856 its product of digits (240), we obtain a palindrome (616).

It can be divided in two parts, 85 and 6, that added together give a triangular number (91 = T13).

The spelling of 856 in words is "eight hundred fifty-six", and thus it is an aban number and an oban number.

Divisors: 1 2 4 8 107 214 428 856