66106813 has 2 divisors, whose sum is σ = 66106814. Its totient is φ = 66106812.

The previous prime is 66106763. The next prime is 66106877. The reversal of 66106813 is 31860166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51222649 + 14884164 = 7157^2 + 3858^2 .

It is a cyclic number.

It is not a de Polignac number, because 66106813 - 2²¹ = 64009661 is a prime.

It is a super-2 number, since 2×66106813² = 8740221450033938, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66106213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33053406 + 33053407.

It is an arithmetic number, because the mean of its divisors is an integer number (33053407).

Almost surely, 2^66106813 is an apocalyptic number.

It is an amenable number.

66106813 is a deficient number, since it is larger than the sum of its proper divisors (1).

66106813 is an equidigital number, since it uses as much as digits as its factorization.

66106813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 66106813 is about 8130.6096327397. The cubic root of 66106813 is about 404.3418931319.

Adding to 66106813 its reverse (31860166), we get a palindrome (97966979).

The spelling of 66106813 in words is "sixty-six million, one hundred six thousand, eight hundred thirteen".