66661417 has 2 divisors, whose sum is σ = 66661418. Its totient is φ = 66661416.

The previous prime is 66661409. The next prime is 66661423. The reversal of 66661417 is 71416666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 38241856 + 28419561 = 6184^2 + 5331^2 .

It is a cyclic number.

It is not a de Polignac number, because 66661417 - 2³ = 66661409 is a prime.

It is not a weakly prime, because it can be changed into another prime (66661447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33330708 + 33330709.

It is an arithmetic number, because the mean of its divisors is an integer number (33330709).

Almost surely, 2^66661417 is an apocalyptic number.

It is an amenable number.

66661417 is a deficient number, since it is larger than the sum of its proper divisors (1).

66661417 is an equidigital number, since it uses as much as digits as its factorization.

66661417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 37.

The square root of 66661417 is about 8164.6443278320. The cubic root of 66661417 is about 405.4694895812.

The spelling of 66661417 in words is "sixty-six million, six hundred sixty-one thousand, four hundred seventeen".