66365521 has 2 divisors, whose sum is σ = 66365522. Its totient is φ = 66365520.

The previous prime is 66365479. The next prime is 66365549. The reversal of 66365521 is 12556366.

66365521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34386496 + 31979025 = 5864^2 + 5655^2 .

It is a cyclic number.

It is not a de Polignac number, because 66365521 - 2¹⁵ = 66332753 is a prime.

It is equal to p_3916546 and since 66365521 and 3916546 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (66365561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33182760 + 33182761.

It is an arithmetic number, because the mean of its divisors is an integer number (33182761).

Almost surely, 2^66365521 is an apocalyptic number.

It is an amenable number.

66365521 is a deficient number, since it is larger than the sum of its proper divisors (1).

66365521 is an equidigital number, since it uses as much as digits as its factorization.

66365521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32400, while the sum is 34.

The square root of 66365521 is about 8146.5036058422. The cubic root of 66365521 is about 404.8686684875.

The spelling of 66365521 in words is "sixty-six million, three hundred sixty-five thousand, five hundred twenty-one".