666385441 has 4 divisors (see below), whose sum is σ = 673255492. Its totient is φ = 659515392.

The previous prime is 666385381. The next prime is 666385469. The reversal of 666385441 is 144583666.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 185504400 + 480881041 = 13620^2 + 21929^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666385441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666385241) 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, 3434880 + ... + 3435073.

It is an arithmetic number, because the mean of its divisors is an integer number (168313873).

Almost surely, 2^666385441 is an apocalyptic number.

It is an amenable number.

666385441 is a deficient number, since it is larger than the sum of its proper divisors (6870051).

666385441 is an equidigital number, since it uses as much as digits as its factorization.

666385441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6870050.

The product of its digits is 414720, while the sum is 43.

The square root of 666385441 is about 25814.4424886535. The cubic root of 666385441 is about 873.4576108356.

The spelling of 666385441 in words is "six hundred sixty-six million, three hundred eighty-five thousand, four hundred forty-one".