138775649 has 2 divisors, whose sum is σ = 138775650. Its totient is φ = 138775648.

The previous prime is 138775633. The next prime is 138775661. The reversal of 138775649 is 946577831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135885649 + 2890000 = 11657^2 + 1700^2 .

It is an emirp because it is prime and its reverse (946577831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138775649 - 2⁴ = 138775633 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 138775597 and 138775606.

It is not a weakly prime, because it can be changed into another prime (138775619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69387824 + 69387825.

It is an arithmetic number, because the mean of its divisors is an integer number (69387825).

Almost surely, 2^138775649 is an apocalyptic number.

It is an amenable number.

138775649 is a deficient number, since it is larger than the sum of its proper divisors (1).

138775649 is an equidigital number, since it uses as much as digits as its factorization.

138775649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1270080, while the sum is 50.

The square root of 138775649 is about 11780.3076784946. The cubic root of 138775649 is about 517.7313009917.

The spelling of 138775649 in words is "one hundred thirty-eight million, seven hundred seventy-five thousand, six hundred forty-nine".