138949243 has 2 divisors, whose sum is σ = 138949244. Its totient is φ = 138949242.

The previous prime is 138949241. The next prime is 138949247. The reversal of 138949243 is 342949831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138949243 - 2¹ = 138949241 is a prime.

Together with 138949241, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 138949243.

It is not a weakly prime, because it can be changed into another prime (138949241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69474621 + 69474622.

It is an arithmetic number, because the mean of its divisors is an integer number (69474622).

Almost surely, 2^138949243 is an apocalyptic number.

138949243 is a deficient number, since it is larger than the sum of its proper divisors (1).

138949243 is an equidigital number, since it uses as much as digits as its factorization.

138949243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 186624, while the sum is 43.

The square root of 138949243 is about 11787.6733497328. The cubic root of 138949243 is about 517.9470871649.

The spelling of 138949243 in words is "one hundred thirty-eight million, nine hundred forty-nine thousand, two hundred forty-three".