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231 = 3711

231 has 8 divisors (see below), whose sum is σ = 384. Its totient is φ = 120.

The previous prime is 229. The next prime is 233. The reversal of 231 is 132.

231 is nontrivially palindromic in base 2.

231 is a nontrivial binomial coefficient, being equal to C(22, 2).

It is an interprime number because it is at equal distance from previous prime (229) and next prime (233).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 231 - 21 = 229 is a prime.

It is a super-2 number, since 2×2312 = 106722, which contains 22 as substring.

It is a partition number, being equal to the number of ways a set of 16 identical objects can be partitioned into subset.

231 is a lucky number.

It is a plaindrome in base 8, base 13 and base 14.

It is a nialpdrome in base 16.

It is a zygodrome in base 2.

It is a congruent number.

It is a panconsummate number.

It is not an unprimeable number, because it can be changed into a prime (233) 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, 16 + ... + 26.

It is an arithmetic number, because the mean of its divisors is an integer number (48).

231 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

231 is the 21-st triangular number and also the 11-th hexagonal number.

231 is a deficient number, since it is larger than the sum of its proper divisors (153).

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

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

The sum of its prime factors is 21.

The product of its digits is 6, while the sum is 6.

The square root of 231 is about 15.1986841536. The cubic root of 231 is about 6.1357924397.

Adding to 231 its reverse (132), we get a palindrome (363).

Subtracting from 231 its reverse (132), we obtain a palindrome (99).

It can be divided in two parts, 2 and 31, that added together give a palindrome (33).

The spelling of 231 in words is "two hundred thirty-one", and thus it is an aban number.

Divisors: 1 3 7 11 21 33 77 231