138649811 has 2 divisors, whose sum is σ = 138649812. Its totient is φ = 138649810.

The previous prime is 138649793. The next prime is 138649813. The reversal of 138649811 is 118946831.

It is a strong prime.

It is an emirp because it is prime and its reverse (118946831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138649811 - 2⁶ = 138649747 is a prime.

It is a super-5 number, since 5×138649811⁵ (a number of 42 digits) contains 55555 as substring.

Together with 138649813, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (138649813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69324905 + 69324906.

It is an arithmetic number, because the mean of its divisors is an integer number (69324906).

Almost surely, 2^138649811 is an apocalyptic number.

138649811 is a deficient number, since it is larger than the sum of its proper divisors (1).

138649811 is an equidigital number, since it uses as much as digits as its factorization.

138649811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41472, while the sum is 41.

The square root of 138649811 is about 11774.9654351934. The cubic root of 138649811 is about 517.5747654275.

The spelling of 138649811 in words is "one hundred thirty-eight million, six hundred forty-nine thousand, eight hundred eleven".