138223181 has 2 divisors, whose sum is σ = 138223182. Its totient is φ = 138223180.

The previous prime is 138223159. The next prime is 138223291. The reversal of 138223181 is 181322831.

138223181 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 137851081 + 372100 = 11741^2 + 610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138223181 is a prime.

It is a super-2 number, since 2×138223181² = 38211295531517522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138223121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69111590 + 69111591.

It is an arithmetic number, because the mean of its divisors is an integer number (69111591).

Almost surely, 2^138223181 is an apocalyptic number.

It is an amenable number.

138223181 is a deficient number, since it is larger than the sum of its proper divisors (1).

138223181 is an equidigital number, since it uses as much as digits as its factorization.

138223181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 29.

The square root of 138223181 is about 11756.8355011032. The cubic root of 138223181 is about 517.0433551755.

The spelling of 138223181 in words is "one hundred thirty-eight million, two hundred twenty-three thousand, one hundred eighty-one".