666718799 has 4 divisors (see below), whose sum is σ = 684738264. Its totient is φ = 648699336.

The previous prime is 666718783. The next prime is 666718823. The reversal of 666718799 is 997817666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 666718799 - 2⁴ = 666718783 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666718739) 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, 9009677 + ... + 9009750.

It is an arithmetic number, because the mean of its divisors is an integer number (171184566).

Almost surely, 2^666718799 is an apocalyptic number.

666718799 is a deficient number, since it is larger than the sum of its proper divisors (18019465).

666718799 is a wasteful number, since it uses less digits than its factorization.

666718799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18019464.

The product of its digits is 6858432, while the sum is 59.

The square root of 666718799 is about 25820.8984932748. The cubic root of 666718799 is about 873.6032350368.

The spelling of 666718799 in words is "six hundred sixty-six million, seven hundred eighteen thousand, seven hundred ninety-nine".