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1806 = 23743

1806 has 16 divisors (see below), whose sum is σ = 4224. Its totient is φ = 504.

The previous prime is 1801. The next prime is 1811. The reversal of 1806 is 6081.

It is an interprime number because it is at equal distance from previous prime (1801) and next prime (1811).

It is a Curzon number.

It is a nialpdrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1801) by changing a digit.

1806 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21 + ... + 63.

It is an arithmetic number, because the mean of its divisors is an integer number (264).

21806 is an apocalyptic number.

It is a pronic number, being equal to 42×43.

It is a practical number, because each smaller number is the sum of distinct divisors of 1806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2112).

1806 is an abundant number, since it is smaller than the sum of its proper divisors (2418).

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

1806 is a wasteful number, since it uses less digits than its factorization.

1806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1806 is about 42.4970587218. The cubic root of 1806 is about 12.1779050055.

Adding to 1806 its reverse (6081), we get a palindrome (7887).

The spelling of 1806 in words is "one thousand, eight hundred six".

Divisors: 1 2 3 6 7 14 21 42 43 86 129 258 301 602 903 1806