138361621 has 2 divisors, whose sum is σ = 138361622. Its totient is φ = 138361620.

The previous prime is 138361579. The next prime is 138361631. The reversal of 138361621 is 126163831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115799121 + 22562500 = 10761^2 + 4750^2 .

It is a cyclic number.

It is not a de Polignac number, because 138361621 - 2⁷ = 138361493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138361631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69180810 + 69180811.

It is an arithmetic number, because the mean of its divisors is an integer number (69180811).

Almost surely, 2^138361621 is an apocalyptic number.

It is an amenable number.

138361621 is a deficient number, since it is larger than the sum of its proper divisors (1).

138361621 is an equidigital number, since it uses as much as digits as its factorization.

138361621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 138361621 is about 11762.7216663492. The cubic root of 138361621 is about 517.2159157104.

The spelling of 138361621 in words is "one hundred thirty-eight million, three hundred sixty-one thousand, six hundred twenty-one".