667857643 has 4 divisors (see below), whose sum is σ = 670217848. Its totient is φ = 665497440.

The previous prime is 667857637. The next prime is 667857649. The reversal of 667857643 is 346758766.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 346758766 = 2 ⋅173379383.

It is an interprime number because it is at equal distance from previous prime (667857637) and next prime (667857649).

It is a cyclic number.

It is not a de Polignac number, because 667857643 - 2⁹ = 667857131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (667857649) 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, 1179678 + ... + 1180243.

It is an arithmetic number, because the mean of its divisors is an integer number (167554462).

Almost surely, 2^667857643 is an apocalyptic number.

667857643 is a deficient number, since it is larger than the sum of its proper divisors (2360205).

667857643 is a wasteful number, since it uses less digits than its factorization.

667857643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2360204.

The product of its digits is 5080320, while the sum is 52.

The square root of 667857643 is about 25842.9418410521. The cubic root of 667857643 is about 874.1003620958.

The spelling of 667857643 in words is "six hundred sixty-seven million, eight hundred fifty-seven thousand, six hundred forty-three".