68647888657 has 4 divisors (see below), whose sum is σ = 68768535780. Its totient is φ = 68527241536.

The previous prime is 68647888619. The next prime is 68647888669. The reversal of 68647888657 is 75688874686.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75688874686 = 2 ⋅37844437343.

It can be written as a sum of positive squares in 2 ways, for example, as 20459297296 + 48188591361 = 143036^2 + 219519^2 .

It is a cyclic number.

It is not a de Polignac number, because 68647888657 - 2¹⁵ = 68647855889 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 68647888657.

It is not an unprimeable number, because it can be changed into a prime (68647888957) 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, 60322708 + ... + 60323845.

It is an arithmetic number, because the mean of its divisors is an integer number (17192133945).

Almost surely, 2^68647888657 is an apocalyptic number.

It is an amenable number.

68647888657 is a deficient number, since it is larger than the sum of its proper divisors (120647123).

68647888657 is a wasteful number, since it uses less digits than its factorization.

68647888657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120647122.

The product of its digits is 867041280, while the sum is 73.

The spelling of 68647888657 in words is "sixty-eight billion, six hundred forty-seven million, eight hundred eighty-eight thousand, six hundred fifty-seven".