138065621 has 2 divisors, whose sum is σ = 138065622. Its totient is φ = 138065620.

The previous prime is 138065617. The next prime is 138065659. The reversal of 138065621 is 126560831.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133287025 + 4778596 = 11545^2 + 2186^2 .

It is a cyclic number.

It is not a de Polignac number, because 138065621 - 2² = 138065617 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138065821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69032810 + 69032811.

It is an arithmetic number, because the mean of its divisors is an integer number (69032811).

Almost surely, 2^138065621 is an apocalyptic number.

It is an amenable number.

138065621 is a deficient number, since it is larger than the sum of its proper divisors (1).

138065621 is an equidigital number, since it uses as much as digits as its factorization.

138065621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 138065621 is about 11750.1328077601. The cubic root of 138065621 is about 516.8468219938.

The spelling of 138065621 in words is "one hundred thirty-eight million, sixty-five thousand, six hundred twenty-one".