668420843 has 4 divisors (see below), whose sum is σ = 668601960. Its totient is φ = 668239728.

The previous prime is 668420771. The next prime is 668420861. The reversal of 668420843 is 348024866.

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 668420843 - 2⁸ = 668420587 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 668420843.

It is not an unprimeable number, because it can be changed into a prime (668420243) 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, 84905 + ... + 92442.

It is an arithmetic number, because the mean of its divisors is an integer number (167150490).

Almost surely, 2^668420843 is an apocalyptic number.

668420843 is a deficient number, since it is larger than the sum of its proper divisors (181117).

668420843 is a wasteful number, since it uses less digits than its factorization.

668420843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181116.

The product of its (nonzero) digits is 221184, while the sum is 41.

The square root of 668420843 is about 25853.8361370223. The cubic root of 668420843 is about 874.3460007740.

The spelling of 668420843 in words is "six hundred sixty-eight million, four hundred twenty thousand, eight hundred forty-three".