66417649 has 2 divisors, whose sum is σ = 66417650. Its totient is φ = 66417648.

The previous prime is 66417619. The next prime is 66417667. The reversal of 66417649 is 94671466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54390625 + 12027024 = 7375^2 + 3468^2 .

It is a cyclic number.

It is not a de Polignac number, because 66417649 - 2⁹ = 66417137 is a prime.

It is a super-2 number, since 2×66417649² = 8822608197374402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66417619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33208824 + 33208825.

It is an arithmetic number, because the mean of its divisors is an integer number (33208825).

Almost surely, 2^66417649 is an apocalyptic number.

It is an amenable number.

66417649 is a deficient number, since it is larger than the sum of its proper divisors (1).

66417649 is an equidigital number, since it uses as much as digits as its factorization.

66417649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 43.

The square root of 66417649 is about 8149.7023872041. The cubic root of 66417649 is about 404.9746445540.

It can be divided in two parts, 664176 and 49, that added together give a square (664225 = 815²).

The spelling of 66417649 in words is "sixty-six million, four hundred seventeen thousand, six hundred forty-nine".