138835409 has 2 divisors, whose sum is σ = 138835410. Its totient is φ = 138835408.

The previous prime is 138835399. The next prime is 138835427. The reversal of 138835409 is 904538831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135955600 + 2879809 = 11660^2 + 1697^2 .

It is a cyclic number.

It is not a de Polignac number, because 138835409 - 2¹² = 138831313 is a prime.

It is not a weakly prime, because it can be changed into another prime (138835709) 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, 69417704 + 69417705.

It is an arithmetic number, because the mean of its divisors is an integer number (69417705).

Almost surely, 2^138835409 is an apocalyptic number.

It is an amenable number.

138835409 is a deficient number, since it is larger than the sum of its proper divisors (1).

138835409 is an equidigital number, since it uses as much as digits as its factorization.

138835409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 103680, while the sum is 41.

The square root of 138835409 is about 11782.8438417896. The cubic root of 138835409 is about 517.8056060126.

The spelling of 138835409 in words is "one hundred thirty-eight million, eight hundred thirty-five thousand, four hundred nine".