138223121 has 2 divisors, whose sum is σ = 138223122. Its totient is φ = 138223120.

The previous prime is 138223103. The next prime is 138223153. The reversal of 138223121 is 121322831.

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., 130873600 + 7349521 = 11440^2 + 2711^2 .

It is a cyclic number.

It is not a de Polignac number, because 138223121 - 2¹⁴ = 138206737 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (138223181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69111560 + 69111561.

It is an arithmetic number, because the mean of its divisors is an integer number (69111561).

Almost surely, 2^138223121 is an apocalyptic number.

It is an amenable number.

138223121 is a deficient number, since it is larger than the sum of its proper divisors (1).

138223121 is an equidigital number, since it uses as much as digits as its factorization.

138223121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 23.

The square root of 138223121 is about 11756.8329493959. The cubic root of 138223121 is about 517.0432803627.

Adding to 138223121 its reverse (121322831), we get a palindrome (259545952).

The spelling of 138223121 in words is "one hundred thirty-eight million, two hundred twenty-three thousand, one hundred twenty-one".