138538777 has 4 divisors (see below), whose sum is σ = 149195620. Its totient is φ = 127881936.

The previous prime is 138538759. The next prime is 138538789. The reversal of 138538777 is 777835831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 777835831 = 13799 ⋅56369.

It can be written as a sum of positive squares in 2 ways, for example, as 25563136 + 112975641 = 5056^2 + 10629^2 .

It is not a de Polignac number, because 138538777 - 2⁷ = 138538649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 138538777.

It is not an unprimeable number, because it can be changed into a prime (138538577) 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, 5328402 + ... + 5328427.

It is an arithmetic number, because the mean of its divisors is an integer number (37298905).

Almost surely, 2^138538777 is an apocalyptic number.

It is an amenable number.

138538777 is a deficient number, since it is larger than the sum of its proper divisors (10656843).

138538777 is a wasteful number, since it uses less digits than its factorization.

138538777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10656842.

The product of its digits is 987840, while the sum is 49.

The square root of 138538777 is about 11770.2496575051. The cubic root of 138538777 is about 517.4365665518.

The spelling of 138538777 in words is "one hundred thirty-eight million, five hundred thirty-eight thousand, seven hundred seventy-seven".