66884557 has 2 divisors, whose sum is σ = 66884558. Its totient is φ = 66884556.

The previous prime is 66884537. The next prime is 66884581. The reversal of 66884557 is 75548866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59382436 + 7502121 = 7706^2 + 2739^2 .

It is a cyclic number.

It is not a de Polignac number, because 66884557 - 2²³ = 58495949 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66884557.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66884537) 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, 33442278 + 33442279.

It is an arithmetic number, because the mean of its divisors is an integer number (33442279).

Almost surely, 2^66884557 is an apocalyptic number.

It is an amenable number.

66884557 is a deficient number, since it is larger than the sum of its proper divisors (1).

66884557 is an equidigital number, since it uses as much as digits as its factorization.

66884557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1612800, while the sum is 49.

The square root of 66884557 is about 8178.2979280532. The cubic root of 66884557 is about 405.9214036506.

The spelling of 66884557 in words is "sixty-six million, eight hundred eighty-four thousand, five hundred fifty-seven".