138742243 has 4 divisors (see below), whose sum is σ = 141016768. Its totient is φ = 136467720.

The previous prime is 138742223. The next prime is 138742283. The reversal of 138742243 is 342247831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 342247831 = 1061 ⋅322571.

It is a cyclic number.

It is not a de Polignac number, because 138742243 - 2⁹ = 138741731 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 138742199 and 138742208.

It is not an unprimeable number, because it can be changed into a prime (138742223) 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 in 3 ways as a sum of consecutive naturals, for example, 1137171 + ... + 1137292.

It is an arithmetic number, because the mean of its divisors is an integer number (35254192).

Almost surely, 2^138742243 is an apocalyptic number.

138742243 is a deficient number, since it is larger than the sum of its proper divisors (2274525).

138742243 is an equidigital number, since it uses as much as digits as its factorization.

138742243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2274524.

The product of its digits is 32256, while the sum is 34.

The square root of 138742243 is about 11778.8897184752. The cubic root of 138742243 is about 517.6897549906.

The spelling of 138742243 in words is "one hundred thirty-eight million, seven hundred forty-two thousand, two hundred forty-three".