68355978209 has 2 divisors, whose sum is σ = 68355978210. Its totient is φ = 68355978208.

The previous prime is 68355978169. The next prime is 68355978241. The reversal of 68355978209 is 90287955386.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54326286400 + 14029691809 = 233080^2 + 118447^2 .

It is a cyclic number.

It is not a de Polignac number, because 68355978209 - 2²⁸ = 68087542753 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (68355978269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34177989104 + 34177989105.

It is an arithmetic number, because the mean of its divisors is an integer number (34177989105).

Almost surely, 2^68355978209 is an apocalyptic number.

It is an amenable number.

68355978209 is a deficient number, since it is larger than the sum of its proper divisors (1).

68355978209 is an equidigital number, since it uses as much as digits as its factorization.

68355978209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32659200, while the sum is 62.

The spelling of 68355978209 in words is "sixty-eight billion, three hundred fifty-five million, nine hundred seventy-eight thousand, two hundred nine".