138374021 has 2 divisors, whose sum is σ = 138374022. Its totient is φ = 138374020.

The previous prime is 138374009. The next prime is 138374081. The reversal of 138374021 is 120473831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138321121 + 52900 = 11761^2 + 230^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138374021 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 (138374081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69187010 + 69187011.

It is an arithmetic number, because the mean of its divisors is an integer number (69187011).

Almost surely, 2^138374021 is an apocalyptic number.

It is an amenable number.

138374021 is a deficient number, since it is larger than the sum of its proper divisors (1).

138374021 is an equidigital number, since it uses as much as digits as its factorization.

138374021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 138374021 is about 11763.2487434382. The cubic root of 138374021 is about 517.2313662516.

The spelling of 138374021 in words is "one hundred thirty-eight million, three hundred seventy-four thousand, twenty-one".