666791817803 has 16 divisors (see below), whose sum is σ = 682701020160. Its totient is φ = 651107808000.

The previous prime is 666791817799. The next prime is 666791817817. The reversal of 666791817803 is 308718197666.

It is a cyclic number.

It is not a de Polignac number, because 666791817803 - 2² = 666791817799 is a prime.

It is a super-2 number, since 2×666791817803² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666791817863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2584763 + ... + 2831003.

It is an arithmetic number, because the mean of its divisors is an integer number (42668813760).

Almost surely, 2^666791817803 is an apocalyptic number.

666791817803 is a deficient number, since it is larger than the sum of its proper divisors (15909202357).

666791817803 is a wasteful number, since it uses less digits than its factorization.

666791817803 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246698.

The product of its (nonzero) digits is 18289152, while the sum is 62.

The spelling of 666791817803 in words is "six hundred sixty-six billion, seven hundred ninety-one million, eight hundred seventeen thousand, eight hundred three".