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1813 = 7237
BaseRepresentation
bin11100010101
32111011
4130111
524223
612221
75200
oct3425
92434
101813
1113a9
121071
13a96
14937
1580d
hex715

1813 has 6 divisors (see below), whose sum is σ = 2166. Its totient is φ = 1512.

The previous prime is 1811. The next prime is 1823. The reversal of 1813 is 3181.

Adding to 1813 its reverse (3181), we get a palindrome (4994).

1813 is nontrivially palindromic in base 6.

It can be written as a sum of positive squares in only one way, i.e., 1764 + 49 = 42^2 + 7^2 .

It is not a de Polignac number, because 1813 - 21 = 1811 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7 and base 13.

It is a junction number, because it is equal to n+sod(n) for n = 1793 and 1802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1811) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 31 + ... + 67.

It is an arithmetic number, because the mean of its divisors is an integer number (361).

21813 is an apocalyptic number.

It is an amenable number.

1813 is a deficient number, since it is larger than the sum of its proper divisors (353).

1813 is an equidigital number, since it uses as much as digits as its factorization.

1813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51 (or 44 counting only the distinct ones).

The product of its digits is 24, while the sum is 13.

The square root of 1813 is about 42.5793377121. The cubic root of 1813 is about 12.1936184488.

The spelling of 1813 in words is "one thousand, eight hundred thirteen".

Divisors: 1 7 37 49 259 1813