66666443 has 4 divisors (see below), whose sum is σ = 69565008. Its totient is φ = 63767880.

The previous prime is 66666437. The next prime is 66666487. The reversal of 66666443 is 34466666.

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 66666443 - 2⁴ = 66666427 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 66666443.

It is not an unprimeable number, because it can be changed into a prime (66666433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1449248 + ... + 1449293.

It is an arithmetic number, because the mean of its divisors is an integer number (17391252).

Almost surely, 2^66666443 is an apocalyptic number.

66666443 is a deficient number, since it is larger than the sum of its proper divisors (2898565).

66666443 is a wasteful number, since it uses less digits than its factorization.

66666443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2898564.

The product of its digits is 373248, while the sum is 41.

The square root of 66666443 is about 8164.9521125356. The cubic root of 66666443 is about 405.4796795758.

The spelling of 66666443 in words is "sixty-six million, six hundred sixty-six thousand, four hundred forty-three".