138147989479021 has 2 divisors, whose sum is σ = 138147989479022. Its totient is φ = 138147989479020.

The previous prime is 138147989478971. The next prime is 138147989479063. The reversal of 138147989479021 is 120974989741831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71052002685225 + 67095986793796 = 8429235^2 + 8191214^2 .

It is a cyclic number.

It is not a de Polignac number, because 138147989479021 - 2¹⁵ = 138147989446253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138147989479921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69073994739510 + 69073994739511.

It is an arithmetic number, because the mean of its divisors is an integer number (69073994739511).

Almost surely, 2^{138147989479021} is an apocalyptic number.

It is an amenable number.

138147989479021 is a deficient number, since it is larger than the sum of its proper divisors (1).

138147989479021 is an equidigital number, since it uses as much as digits as its factorization.

138147989479021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 219469824, while the sum is 73.

The spelling of 138147989479021 in words is "one hundred thirty-eight trillion, one hundred forty-seven billion, nine hundred eighty-nine million, four hundred seventy-nine thousand, twenty-one".