138841993 has 4 divisors (see below), whose sum is σ = 139089168. Its totient is φ = 138594820.

The previous prime is 138841981. The next prime is 138842027. The reversal of 138841993 is 399148831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 138841993 - 2¹³ = 138833801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138841943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122743 + ... + 123868.

It is an arithmetic number, because the mean of its divisors is an integer number (34772292).

Almost surely, 2^138841993 is an apocalyptic number.

It is an amenable number.

138841993 is a deficient number, since it is larger than the sum of its proper divisors (247175).

138841993 is an equidigital number, since it uses as much as digits as its factorization.

138841993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247174.

The product of its digits is 186624, while the sum is 46.

The square root of 138841993 is about 11783.1232277355. The cubic root of 138841993 is about 517.8137911921.

The spelling of 138841993 in words is "one hundred thirty-eight million, eight hundred forty-one thousand, nine hundred ninety-three".