138941009 has 2 divisors, whose sum is σ = 138941010. Its totient is φ = 138941008.

The previous prime is 138941003. The next prime is 138941057. The reversal of 138941009 is 900149831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 132181009 + 6760000 = 11497^2 + 2600^2 .

It is a cyclic number.

It is not a de Polignac number, because 138941009 - 2⁴ = 138940993 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138941009.

It is not a weakly prime, because it can be changed into another prime (138941003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69470504 + 69470505.

It is an arithmetic number, because the mean of its divisors is an integer number (69470505).

Almost surely, 2^138941009 is an apocalyptic number.

It is an amenable number.

138941009 is a deficient number, since it is larger than the sum of its proper divisors (1).

138941009 is an equidigital number, since it uses as much as digits as its factorization.

138941009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 138941009 is about 11787.3240814020. The cubic root of 138941009 is about 517.9368559455.

The spelling of 138941009 in words is "one hundred thirty-eight million, nine hundred forty-one thousand, nine".