138068787582821 has 2 divisors, whose sum is σ = 138068787582822. Its totient is φ = 138068787582820.

The previous prime is 138068787582809. The next prime is 138068787582829. The reversal of 138068787582821 is 128285787860831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74217277353025 + 63851510229796 = 8614945^2 + 7990714^2 .

It is a cyclic number.

It is not a de Polignac number, because 138068787582821 - 2⁴² = 133670741071717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138068787582829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69034393791410 + 69034393791411.

It is an arithmetic number, because the mean of its divisors is an integer number (69034393791411).

Almost surely, 2^{138068787582821} is an apocalyptic number.

It is an amenable number.

138068787582821 is a deficient number, since it is larger than the sum of its proper divisors (1).

138068787582821 is an equidigital number, since it uses as much as digits as its factorization.

138068787582821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 578027520, while the sum is 74.

The spelling of 138068787582821 in words is "one hundred thirty-eight trillion, sixty-eight billion, seven hundred eighty-seven million, five hundred eighty-two thousand, eight hundred twenty-one".