138645233 has 4 divisors (see below), whose sum is σ = 139657380. Its totient is φ = 137633088.

The previous prime is 138645211. The next prime is 138645239. The reversal of 138645233 is 332546831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 332546831 = 9059 ⋅36709.

It can be written as a sum of positive squares in 2 ways, for example, as 34951744 + 103693489 = 5912^2 + 10183^2 .

It is a cyclic number.

It is not a de Polignac number, because 138645233 - 2²⁴ = 121868017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 138645193 and 138645202.

It is not an unprimeable number, because it can be changed into a prime (138645239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 505868 + ... + 506141.

It is an arithmetic number, because the mean of its divisors is an integer number (34914345).

Almost surely, 2^138645233 is an apocalyptic number.

It is an amenable number.

138645233 is a deficient number, since it is larger than the sum of its proper divisors (1012147).

138645233 is a wasteful number, since it uses less digits than its factorization.

138645233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1012146.

The product of its digits is 51840, while the sum is 35.

The square root of 138645233 is about 11774.7710381136. The cubic root of 138645233 is about 517.5690688616.

The spelling of 138645233 in words is "one hundred thirty-eight million, six hundred forty-five thousand, two hundred thirty-three".