66181513 has 2 divisors, whose sum is σ = 66181514. Its totient is φ = 66181512.

The previous prime is 66181487. The next prime is 66181529. The reversal of 66181513 is 31518166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50523664 + 15657849 = 7108^2 + 3957^2 .

It is a cyclic number.

It is not a de Polignac number, because 66181513 - 2⁵ = 66181481 is a prime.

It is not a weakly prime, because it can be changed into another prime (66181543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33090756 + 33090757.

It is an arithmetic number, because the mean of its divisors is an integer number (33090757).

Almost surely, 2^66181513 is an apocalyptic number.

It is an amenable number.

66181513 is a deficient number, since it is larger than the sum of its proper divisors (1).

66181513 is an equidigital number, since it uses as much as digits as its factorization.

66181513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 31.

The square root of 66181513 is about 8135.2020872256. The cubic root of 66181513 is about 404.4941364904.

Adding to 66181513 its reverse (31518166), we get a palindrome (97699679).

The spelling of 66181513 in words is "sixty-six million, one hundred eighty-one thousand, five hundred thirteen".