138240061 has 2 divisors, whose sum is σ = 138240062. Its totient is φ = 138240060.

The previous prime is 138239999. The next prime is 138240079. The reversal of 138240061 is 160042831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 108056025 + 30184036 = 10395^2 + 5494^2 .

It is a cyclic number.

It is not a de Polignac number, because 138240061 - 2²⁵ = 104685629 is a prime.

It is a super-2 number, since 2×138240061² = 38220628930567442, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138240761) 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, 69120030 + 69120031.

It is an arithmetic number, because the mean of its divisors is an integer number (69120031).

Almost surely, 2^138240061 is an apocalyptic number.

It is an amenable number.

138240061 is a deficient number, since it is larger than the sum of its proper divisors (1).

138240061 is an equidigital number, since it uses as much as digits as its factorization.

138240061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 138240061 is about 11757.5533594366. The cubic root of 138240061 is about 517.0644016612.

Adding to 138240061 its reverse (160042831), we get a palindrome (298282892).

The spelling of 138240061 in words is "one hundred thirty-eight million, two hundred forty thousand, sixty-one".