666789443 has 2 divisors, whose sum is σ = 666789444. Its totient is φ = 666789442.

The previous prime is 666789421. The next prime is 666789451. The reversal of 666789443 is 344987666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666789443 - 2¹⁸ = 666527299 is a prime.

It is a super-2 number, since 2×666789443² = 889216322592500498, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (666789413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333394721 + 333394722.

It is an arithmetic number, because the mean of its divisors is an integer number (333394722).

Almost surely, 2^666789443 is an apocalyptic number.

666789443 is a deficient number, since it is larger than the sum of its proper divisors (1).

666789443 is an equidigital number, since it uses as much as digits as its factorization.

666789443 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5225472, while the sum is 53.

The square root of 666789443 is about 25822.2664187325. The cubic root of 666789443 is about 873.6340889477.

The spelling of 666789443 in words is "six hundred sixty-six million, seven hundred eighty-nine thousand, four hundred forty-three".