138531893 has 2 divisors, whose sum is σ = 138531894. Its totient is φ = 138531892.

The previous prime is 138531851. The next prime is 138531917. The reversal of 138531893 is 398135831.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91718929 + 46812964 = 9577^2 + 6842^2 .

It is an emirp because it is prime and its reverse (398135831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138531893 - 2²⁶ = 71423029 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138531893.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138531803) 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, 69265946 + 69265947.

It is an arithmetic number, because the mean of its divisors is an integer number (69265947).

Almost surely, 2^138531893 is an apocalyptic number.

It is an amenable number.

138531893 is a deficient number, since it is larger than the sum of its proper divisors (1).

138531893 is an equidigital number, since it uses as much as digits as its factorization.

138531893 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 41.

The square root of 138531893 is about 11769.9572216725. The cubic root of 138531893 is about 517.4279959253.

The spelling of 138531893 in words is "one hundred thirty-eight million, five hundred thirty-one thousand, eight hundred ninety-three".