668891335778 has 16 divisors (see below), whose sum is σ = 1006030471680. Its totient is φ = 333548041200.

The previous prime is 668891335757. The next prime is 668891335829. The reversal of 668891335778 is 877533198866.

It is a happy number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7573493 + ... + 7661303.

It is an arithmetic number, because the mean of its divisors is an integer number (62876904480).

Almost surely, 2^668891335778 is an apocalyptic number.

668891335778 is a deficient number, since it is larger than the sum of its proper divisors (337139135902).

668891335778 is a wasteful number, since it uses less digits than its factorization.

668891335778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97993.

The product of its digits is 365783040, while the sum is 71.

The spelling of 668891335778 in words is "six hundred sixty-eight billion, eight hundred ninety-one million, three hundred thirty-five thousand, seven hundred seventy-eight".