666550306 has 4 divisors (see below), whose sum is σ = 999825462. Its totient is φ = 333275152.

The previous prime is 666550303. The next prime is 666550309. The reversal of 666550306 is 603055666.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 603055666 = 2 ⋅301527833.

It is an interprime number because it is at equal distance from previous prime (666550303) and next prime (666550309).

It can be written as a sum of positive squares in only one way, i.e., 660747025 + 5803281 = 25705^2 + 2409^2 .

It is not an unprimeable number, because it can be changed into a prime (666550303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166637575 + ... + 166637578.

Almost surely, 2^666550306 is an apocalyptic number.

666550306 is a deficient number, since it is larger than the sum of its proper divisors (333275156).

666550306 is a wasteful number, since it uses less digits than its factorization.

666550306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333275155.

The product of its (nonzero) digits is 97200, while the sum is 37.

The square root of 666550306 is about 25817.6355617628. The cubic root of 666550306 is about 873.5296365764.

The spelling of 666550306 in words is "six hundred sixty-six million, five hundred fifty thousand, three hundred six".