136867781 has 2 divisors, whose sum is σ = 136867782. Its totient is φ = 136867780.

The previous prime is 136867777. The next prime is 136867813. The reversal of 136867781 is 187768631.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 117375556 + 19492225 = 10834^2 + 4415^2 .

It is a cyclic number.

It is not a de Polignac number, because 136867781 - 2² = 136867777 is a prime.

It is a super-2 number, since 2×136867781² = 37465578951727922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (136867751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68433890 + 68433891.

It is an arithmetic number, because the mean of its divisors is an integer number (68433891).

Almost surely, 2^136867781 is an apocalyptic number.

It is an amenable number.

136867781 is a deficient number, since it is larger than the sum of its proper divisors (1).

136867781 is an equidigital number, since it uses as much as digits as its factorization.

136867781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 338688, while the sum is 47.

The square root of 136867781 is about 11699.0504315521. The cubic root of 136867781 is about 515.3477790427.

The spelling of 136867781 in words is "one hundred thirty-six million, eight hundred sixty-seven thousand, seven hundred eighty-one".