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BaseRepresentation
bin11100001111
32110221
4130033
524212
612211
75161
oct3417
92427
101807
1113a3
121067
13a90
14931
15807
hex70f

1807 has 4 divisors (see below), whose sum is σ = 1960. Its totient is φ = 1656.

The previous prime is 1801. The next prime is 1811. The reversal of 1807 is 7081.

Adding to 1807 its reverse (7081), we get a palindrome (8888).

It can be divided in two parts, 1 and 807, that added together give a palindrome (808).

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7081 = 7397.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-1807 is a prime.

It is the 43-rd Hogben number.

It is a Duffinian number.

It is a nialpdrome in base 13 and base 14.

It is a zygodrome in base 2.

It is a congruent number.

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

It is a nontrivial repunit in base 42.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57 + ... + 82.

It is an arithmetic number, because the mean of its divisors is an integer number (490).

21807 is an apocalyptic number.

1807 is a deficient number, since it is larger than the sum of its proper divisors (153).

1807 is a wasteful number, since it uses less digits than its factorization.

1807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 1807 is about 42.5088226137. The cubic root of 1807 is about 12.1801522662.

The spelling of 1807 in words is "one thousand, eight hundred seven".

Divisors: 1 13 139 1807