66131111 has 2 divisors, whose sum is σ = 66131112. Its totient is φ = 66131110.

The previous prime is 66131089. The next prime is 66131113. The reversal of 66131111 is 11113166.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66131111 is a prime.

Together with 66131113, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66131113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33065555 + 33065556.

It is an arithmetic number, because the mean of its divisors is an integer number (33065556).

Almost surely, 2^66131111 is an apocalyptic number.

66131111 is a deficient number, since it is larger than the sum of its proper divisors (1).

66131111 is an equidigital number, since it uses as much as digits as its factorization.

66131111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108, while the sum is 20.

The square root of 66131111 is about 8132.1037253591. The cubic root of 66131111 is about 404.3914265834.

Adding to 66131111 its reverse (11113166), we get a palindrome (77244277).

The spelling of 66131111 in words is "sixty-six million, one hundred thirty-one thousand, one hundred eleven".