668138495099 has 4 divisors (see below), whose sum is σ = 668891752464. Its totient is φ = 667385237736.

The previous prime is 668138495083. The next prime is 668138495113. The reversal of 668138495099 is 990594831866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 990594831866 = 2 ⋅495297415933.

It is a cyclic number.

It is not a de Polignac number, because 668138495099 - 2⁴ = 668138495083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668138435099) 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, 376627352 + ... + 376629125.

It is an arithmetic number, because the mean of its divisors is an integer number (167222938116).

Almost surely, 2^668138495099 is an apocalyptic number.

668138495099 is a deficient number, since it is larger than the sum of its proper divisors (753257365).

668138495099 is an equidigital number, since it uses as much as digits as its factorization.

668138495099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 753257364.

The product of its (nonzero) digits is 100776960, while the sum is 68.

The spelling of 668138495099 in words is "six hundred sixty-eight billion, one hundred thirty-eight million, four hundred ninety-five thousand, ninety-nine".