138543409 has 2 divisors, whose sum is σ = 138543410. Its totient is φ = 138543408.

The previous prime is 138543401. The next prime is 138543413. The reversal of 138543409 is 904345831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 136072225 + 2471184 = 11665^2 + 1572^2 .

It is a cyclic number.

It is not a de Polignac number, because 138543409 - 2³ = 138543401 is a prime.

It is not a weakly prime, because it can be changed into another prime (138543401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69271704 + 69271705.

It is an arithmetic number, because the mean of its divisors is an integer number (69271705).

Almost surely, 2^138543409 is an apocalyptic number.

It is an amenable number.

138543409 is a deficient number, since it is larger than the sum of its proper divisors (1).

138543409 is an equidigital number, since it uses as much as digits as its factorization.

138543409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 138543409 is about 11770.4464231396. The cubic root of 138543409 is about 517.4423332632.

The spelling of 138543409 in words is "one hundred thirty-eight million, five hundred forty-three thousand, four hundred nine".