138000221 has 2 divisors, whose sum is σ = 138000222. Its totient is φ = 138000220.

The previous prime is 138000217. The next prime is 138000223. The reversal of 138000221 is 122000831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 134884996 + 3115225 = 11614^2 + 1765^2 .

It is a cyclic number.

It is not a de Polignac number, because 138000221 - 2² = 138000217 is a prime.

Together with 138000223, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138000221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138000223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69000110 + 69000111.

It is an arithmetic number, because the mean of its divisors is an integer number (69000111).

Almost surely, 2^138000221 is an apocalyptic number.

It is an amenable number.

138000221 is a deficient number, since it is larger than the sum of its proper divisors (1).

138000221 is an equidigital number, since it uses as much as digits as its factorization.

138000221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 138000221 is about 11747.3495308516. The cubic root of 138000221 is about 516.7652010938.

The spelling of 138000221 in words is "one hundred thirty-eight million, two hundred twenty-one", and thus it is an aban number.