666717803 has 4 divisors (see below), whose sum is σ = 667806048. Its totient is φ = 665629560.

The previous prime is 666717797. The next prime is 666717811. The reversal of 666717803 is 308717666.

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: 308717666 = 2 ⋅154358833.

It is a cyclic number.

It is not a de Polignac number, because 666717803 - 2⁴ = 666717787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666717823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 543203 + ... + 544428.

It is an arithmetic number, because the mean of its divisors is an integer number (166951512).

Almost surely, 2^666717803 is an apocalyptic number.

666717803 is a deficient number, since it is larger than the sum of its proper divisors (1088245).

666717803 is a wasteful number, since it uses less digits than its factorization.

666717803 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1088244.

The product of its (nonzero) digits is 254016, while the sum is 44.

The square root of 666717803 is about 25820.8792065646. The cubic root of 666717803 is about 873.6028000162.

The spelling of 666717803 in words is "six hundred sixty-six million, seven hundred seventeen thousand, eight hundred three".