66618247 has 2 divisors, whose sum is σ = 66618248. Its totient is φ = 66618246.

The previous prime is 66618239. The next prime is 66618259. The reversal of 66618247 is 74281666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66618247 - 2³ = 66618239 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66613247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33309123 + 33309124.

It is an arithmetic number, because the mean of its divisors is an integer number (33309124).

Almost surely, 2^66618247 is an apocalyptic number.

66618247 is a deficient number, since it is larger than the sum of its proper divisors (1).

66618247 is an equidigital number, since it uses as much as digits as its factorization.

66618247 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 40.

The square root of 66618247 is about 8162.0001837785. Note that the first 3 decimals coincide. The cubic root of 66618247 is about 405.3819431984.

The spelling of 66618247 in words is "sixty-six million, six hundred eighteen thousand, two hundred forty-seven".