511111 has 2 divisors, whose sum is σ = 511112. Its totient is φ = 511110.

The previous prime is 511109. The next prime is 511123. The reversal of 511111 is 111115.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 511111 - 2¹ = 511109 is a prime.

It is a super-2 number, since 2×511111² = 522468908642, which contains 22 as substring.

Together with 511109, it forms a pair of twin primes.

It is a Chen prime.

511111 is a modest number, since divided by 1111 gives 51 as remainder.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (511151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 255555 + 255556.

It is an arithmetic number, because the mean of its divisors is an integer number (255556).

2⁵¹¹¹¹¹ is an apocalyptic number.

511111 is a deficient number, since it is larger than the sum of its proper divisors (1).

511111 is an equidigital number, since it uses as much as digits as its factorization.

511111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5, while the sum is 10.

The square root of 511111 is about 714.9202752755. The cubic root of 511111 is about 79.9536710922.

Adding to 511111 its reverse (111115), we get a palindrome (622226).

It can be divided in two parts, 5 and 11111, that multiplied together give a palindrome (55555).

The spelling of 511111 in words is "five hundred eleven thousand, one hundred eleven".