66297557 has 2 divisors, whose sum is σ = 66297558. Its totient is φ = 66297556.

The previous prime is 66297547. The next prime is 66297563. The reversal of 66297557 is 75579266.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62078641 + 4218916 = 7879^2 + 2054^2 .

It is a cyclic number.

It is not a de Polignac number, because 66297557 - 2⁶ = 66297493 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66297527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33148778 + 33148779.

It is an arithmetic number, because the mean of its divisors is an integer number (33148779).

Almost surely, 2^66297557 is an apocalyptic number.

It is an amenable number.

66297557 is a deficient number, since it is larger than the sum of its proper divisors (1).

66297557 is an equidigital number, since it uses as much as digits as its factorization.

66297557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 793800, while the sum is 47.

The square root of 66297557 is about 8142.3311772489. The cubic root of 66297557 is about 404.7304145056.

The spelling of 66297557 in words is "sixty-six million, two hundred ninety-seven thousand, five hundred fifty-seven".