68778557 has 2 divisors, whose sum is σ = 68778558. Its totient is φ = 68778556.

The previous prime is 68778551. The next prime is 68778587. The reversal of 68778557 is 75587786.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49716601 + 19061956 = 7051^2 + 4366^2 .

It is a cyclic number.

It is not a de Polignac number, because 68778557 - 2¹⁴ = 68762173 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 68778499 and 68778508.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68778551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34389278 + 34389279.

It is an arithmetic number, because the mean of its divisors is an integer number (34389279).

Almost surely, 2^68778557 is an apocalyptic number.

It is an amenable number.

68778557 is a deficient number, since it is larger than the sum of its proper divisors (1).

68778557 is an equidigital number, since it uses as much as digits as its factorization.

68778557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3292800, while the sum is 53.

The square root of 68778557 is about 8293.2838489949. The cubic root of 68778557 is about 409.7173483154.

The spelling of 68778557 in words is "sixty-eight million, seven hundred seventy-eight thousand, five hundred fifty-seven".