68128710581989 has 4 divisors (see below), whose sum is σ = 68765427503424. Its totient is φ = 67491993660556.

The previous prime is 68128710581977. The next prime is 68128710582013. The reversal of 68128710581989 is 98918501782186.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 68128710581989 - 2⁷ = 68128710581861 is a prime.

It is a super-2 number, since 2×68128710581989² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68128710581909) 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, 318358460557 + ... + 318358460770.

It is an arithmetic number, because the mean of its divisors is an integer number (17191356875856).

Almost surely, 2^{68128710581989} is an apocalyptic number.

It is an amenable number.

68128710581989 is a deficient number, since it is larger than the sum of its proper divisors (636716921435).

68128710581989 is a wasteful number, since it uses less digits than its factorization.

68128710581989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636716921434.

The product of its (nonzero) digits is 139345920, while the sum is 73.

The spelling of 68128710581989 in words is "sixty-eight trillion, one hundred twenty-eight billion, seven hundred ten million, five hundred eighty-one thousand, nine hundred eighty-nine".