138689649 has 24 divisors (see below), whose sum is σ = 233625600. Its totient is φ = 79249464.

The previous prime is 138689641. The next prime is 138689651. The reversal of 138689649 is 946986831.

It is not a de Polignac number, because 138689649 - 2³ = 138689641 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 138689595 and 138689604.

It is not an unprimeable number, because it can be changed into a prime (138689641) 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 in 23 ways as a sum of consecutive naturals, for example, 19377 + ... + 25550.

It is an arithmetic number, because the mean of its divisors is an integer number (9734400).

Almost surely, 2^138689649 is an apocalyptic number.

It is an amenable number.

138689649 is a deficient number, since it is larger than the sum of its proper divisors (94935951).

138689649 is an equidigital number, since it uses as much as digits as its factorization.

138689649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44954 (or 44937 counting only the distinct ones).

The product of its digits is 2239488, while the sum is 54.

The square root of 138689649 is about 11776.6569534822. The cubic root of 138689649 is about 517.6243319550.

It can be divided in two parts, 1386896 and 49, that added together give a triangular number (1386945 = T₁₆₆₅).

The spelling of 138689649 in words is "one hundred thirty-eight million, six hundred eighty-nine thousand, six hundred forty-nine".