66489217 has 2 divisors, whose sum is σ = 66489218. Its totient is φ = 66489216.

The previous prime is 66489211. The next prime is 66489229. The reversal of 66489217 is 71298466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63377521 + 3111696 = 7961^2 + 1764^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66489217 is a prime.

It is not a weakly prime, because it can be changed into another prime (66489211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33244608 + 33244609.

It is an arithmetic number, because the mean of its divisors is an integer number (33244609).

Almost surely, 2^66489217 is an apocalyptic number.

It is an amenable number.

66489217 is a deficient number, since it is larger than the sum of its proper divisors (1).

66489217 is an equidigital number, since it uses as much as digits as its factorization.

66489217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 43.

The square root of 66489217 is about 8154.0920401968. The cubic root of 66489217 is about 405.1200517953.

Subtracting 66489217 from its reverse (71298466), we obtain a square (4809249 = 2193²).

The spelling of 66489217 in words is "sixty-six million, four hundred eighty-nine thousand, two hundred seventeen".