68642123689 has 4 divisors (see below), whose sum is σ = 68897299140. Its totient is φ = 68386948240.

The previous prime is 68642123681. The next prime is 68642123723. The reversal of 68642123689 is 98632124686.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98632124686 = 2 ⋅49316062343.

It can be written as a sum of positive squares in 2 ways, for example, as 30847653225 + 37794470464 = 175635^2 + 194408^2 .

It is a cyclic number.

It is not a de Polignac number, because 68642123689 - 2³ = 68642123681 is a prime.

It is a super-2 number, since 2×68642123689² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68642123681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127587322 + ... + 127587859.

It is an arithmetic number, because the mean of its divisors is an integer number (17224324785).

Almost surely, 2^68642123689 is an apocalyptic number.

It is an amenable number.

68642123689 is a deficient number, since it is larger than the sum of its proper divisors (255175451).

68642123689 is a wasteful number, since it uses less digits than its factorization.

68642123689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255175450.

The product of its digits is 5971968, while the sum is 55.

The spelling of 68642123689 in words is "sixty-eight billion, six hundred forty-two million, one hundred twenty-three thousand, six hundred eighty-nine".