666667819787 has 8 divisors (see below), whose sum is σ = 668268075600. Its totient is φ = 665068078080.

The previous prime is 666667819757. The next prime is 666667819799. The reversal of 666667819787 is 787918766666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 666667819787 - 2¹⁶ = 666667754251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666667819757) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2534087 + ... + 2784767.

It is an arithmetic number, because the mean of its divisors is an integer number (83533509450).

Almost surely, 2^666667819787 is an apocalyptic number.

666667819787 is a deficient number, since it is larger than the sum of its proper divisors (1600255813).

666667819787 is a wasteful number, since it uses less digits than its factorization.

666667819787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257053.

The product of its digits is 1536288768, while the sum is 77.

The spelling of 666667819787 in words is "six hundred sixty-six billion, six hundred sixty-seven million, eight hundred nineteen thousand, seven hundred eighty-seven".