138753221 has 2 divisors, whose sum is σ = 138753222. Its totient is φ = 138753220.

The previous prime is 138753211. The next prime is 138753239. The reversal of 138753221 is 122357831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 102921025 + 35832196 = 10145^2 + 5986^2 .

It is a cyclic number.

It is not a de Polignac number, because 138753221 - 2¹⁰ = 138752197 is a prime.

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 (138753211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69376610 + 69376611.

It is an arithmetic number, because the mean of its divisors is an integer number (69376611).

Almost surely, 2^138753221 is an apocalyptic number.

It is an amenable number.

138753221 is a deficient number, since it is larger than the sum of its proper divisors (1).

138753221 is an equidigital number, since it uses as much as digits as its factorization.

138753221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 32.

The square root of 138753221 is about 11779.3557124318. The cubic root of 138753221 is about 517.7034087227.

The spelling of 138753221 in words is "one hundred thirty-eight million, seven hundred fifty-three thousand, two hundred twenty-one".