138866449 has 2 divisors, whose sum is σ = 138866450. Its totient is φ = 138866448.

The previous prime is 138866447. The next prime is 138866473. The reversal of 138866449 is 944668831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81000000 + 57866449 = 9000^2 + 7607^2 .

It is a cyclic number.

It is not a de Polignac number, because 138866449 - 2¹ = 138866447 is a prime.

Together with 138866447, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (138866443) 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, 69433224 + 69433225.

It is an arithmetic number, because the mean of its divisors is an integer number (69433225).

Almost surely, 2^138866449 is an apocalyptic number.

It is an amenable number.

138866449 is a deficient number, since it is larger than the sum of its proper divisors (1).

138866449 is an equidigital number, since it uses as much as digits as its factorization.

138866449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 995328, while the sum is 49.

The square root of 138866449 is about 11784.1609374618. The cubic root of 138866449 is about 517.8441924426.

The spelling of 138866449 in words is "one hundred thirty-eight million, eight hundred sixty-six thousand, four hundred forty-nine".