811 has 2 divisors, whose sum is σ = 812. Its totient is φ = 810.

The previous prime is 809. The next prime is 821. The reversal of 811 is 118.

Adding to 811 its reverse (118), we get a palindrome (929).

It can be divided in two parts, 8 and 11, that multiplied together give a palindrome (88).

811 = 9^{2} + 10^{2} + ... + 14^{2}.

811 is an esthetic number in base 11, because in such base its adjacent digits differ by 1.

It is an a-pointer prime, because the next prime (821) can be obtained adding 811 to its sum of digits (10).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 811 - 2^{1} = 809 is a prime.

Together with 809, it forms a pair of twin primes.

It is a Chen prime.

811 is a modest number, since divided by 11 gives 8 as remainder.

It is a plaindrome in base 7, base 11 and base 12.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405 + 406.

It is an arithmetic number, because the mean of its divisors is an integer number (406).

811 is a deficient number, since it is larger than the sum of its proper divisors (1).

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

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

The product of its digits is 8, while the sum is 10.

The square root of 811 is about 28.4780617318. The cubic root of 811 is about 9.3255320298.

The spelling of 811 in words is "eight hundred eleven", and thus it is an aban number and an oban number.

• e-mail: info -at- numbersaplenty.com • Privacy notice • done in 0.067 sec. • engine limits •