666550307 has 4 divisors (see below), whose sum is σ = 666666480. Its totient is φ = 666434136.

The previous prime is 666550303. The next prime is 666550309. The reversal of 666550307 is 703055666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 703055666 = 2 ⋅351527833.

It is a cyclic number.

It is not a de Polignac number, because 666550307 - 2² = 666550303 is a prime.

It is a Duffinian number.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49007 + ... + 61112.

It is an arithmetic number, because the mean of its divisors is an integer number (166666620).

Almost surely, 2^666550307 is an apocalyptic number.

666550307 is a deficient number, since it is larger than the sum of its proper divisors (116173).

666550307 is a wasteful number, since it uses less digits than its factorization.

666550307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116172.

The product of its (nonzero) digits is 113400, while the sum is 38.

The square root of 666550307 is about 25817.6355811294. The cubic root of 666550307 is about 873.5296370132.

The spelling of 666550307 in words is "six hundred sixty-six million, five hundred fifty thousand, three hundred seven".