66287521 has 2 divisors, whose sum is σ = 66287522. Its totient is φ = 66287520.

The previous prime is 66287509. The next prime is 66287527. The reversal of 66287521 is 12578266.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66194496 + 93025 = 8136^2 + 305^2 .

It is a cyclic number.

It is not a de Polignac number, because 66287521 - 2⁵ = 66287489 is a prime.

It is not a weakly prime, because it can be changed into another prime (66287527) 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, 33143760 + 33143761.

It is an arithmetic number, because the mean of its divisors is an integer number (33143761).

Almost surely, 2^66287521 is an apocalyptic number.

It is an amenable number.

66287521 is a deficient number, since it is larger than the sum of its proper divisors (1).

66287521 is an equidigital number, since it uses as much as digits as its factorization.

66287521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40320, while the sum is 37.

The square root of 66287521 is about 8141.7148685028. The cubic root of 66287521 is about 404.7099910310.

The spelling of 66287521 in words is "sixty-six million, two hundred eighty-seven thousand, five hundred twenty-one".