138533909 has 2 divisors, whose sum is σ = 138533910. Its totient is φ = 138533908.

The previous prime is 138533881. The next prime is 138533911. The reversal of 138533909 is 909335831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 114425809 + 24108100 = 10697^2 + 4910^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138533909 is a prime.

Together with 138533911, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_7833884 and since 138533909 and 7833884 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138533939) 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, 69266954 + 69266955.

It is an arithmetic number, because the mean of its divisors is an integer number (69266955).

Almost surely, 2^138533909 is an apocalyptic number.

It is an amenable number.

138533909 is a deficient number, since it is larger than the sum of its proper divisors (1).

138533909 is an equidigital number, since it uses as much as digits as its factorization.

138533909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 87480, while the sum is 41.

The square root of 138533909 is about 11770.0428631335. The cubic root of 138533909 is about 517.4305058883.

The spelling of 138533909 in words is "one hundred thirty-eight million, five hundred thirty-three thousand, nine hundred nine".