66698657 has 2 divisors, whose sum is σ = 66698658. Its totient is φ = 66698656.

The previous prime is 66698651. The next prime is 66698659. The reversal of 66698657 is 75689666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45914176 + 20784481 = 6776^2 + 4559^2 .

It is a cyclic number.

It is not a de Polignac number, because 66698657 - 2¹⁰ = 66697633 is a prime.

It is a super-4 number, since 4×66698657⁴ (a number of 32 digits) contains 4444 as substring.

Together with 66698659, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 66698599 and 66698608.

It is not a weakly prime, because it can be changed into another prime (66698651) 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, 33349328 + 33349329.

It is an arithmetic number, because the mean of its divisors is an integer number (33349329).

Almost surely, 2^66698657 is an apocalyptic number.

It is an amenable number.

66698657 is a deficient number, since it is larger than the sum of its proper divisors (1).

66698657 is an equidigital number, since it uses as much as digits as its factorization.

66698657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3265920, while the sum is 53.

The square root of 66698657 is about 8166.9245741589. The cubic root of 66698657 is about 405.5449798901.

The spelling of 66698657 in words is "sixty-six million, six hundred ninety-eight thousand, six hundred fifty-seven".