668138799 has 8 divisors (see below), whose sum is σ = 929584512. Its totient is φ = 426059480.

The previous prime is 668138789. The next prime is 668138803. The reversal of 668138799 is 997831866.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 668138799 - 2⁷ = 668138671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668138749) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4841517 + ... + 4841654.

It is an arithmetic number, because the mean of its divisors is an integer number (116198064).

Almost surely, 2^668138799 is an apocalyptic number.

668138799 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

668138799 is a deficient number, since it is larger than the sum of its proper divisors (261445713).

668138799 is a wasteful number, since it uses less digits than its factorization.

668138799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9683197.

The product of its digits is 3919104, while the sum is 57.

The square root of 668138799 is about 25848.3809744440. The cubic root of 668138799 is about 874.2230050399.

The spelling of 668138799 in words is "six hundred sixty-eight million, one hundred thirty-eight thousand, seven hundred ninety-nine".