138777893 has 4 divisors (see below), whose sum is σ = 139384140. Its totient is φ = 138171648.

The previous prime is 138777889. The next prime is 138777901. The reversal of 138777893 is 398777831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 398777831 = 31 ⋅12863801.

It can be written as a sum of positive squares in 2 ways, for example, as 122921569 + 15856324 = 11087^2 + 3982^2 .

It is a cyclic number.

It is not a de Polignac number, because 138777893 - 2² = 138777889 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138777833) 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, 302780 + ... + 303237.

It is an arithmetic number, because the mean of its divisors is an integer number (34846035).

Almost surely, 2^138777893 is an apocalyptic number.

It is an amenable number.

138777893 is a deficient number, since it is larger than the sum of its proper divisors (606247).

138777893 is an equidigital number, since it uses as much as digits as its factorization.

138777893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606246.

The product of its digits is 1778112, while the sum is 53.

The square root of 138777893 is about 11780.4029218020. The cubic root of 138777893 is about 517.7340915456.

The spelling of 138777893 in words is "one hundred thirty-eight million, seven hundred seventy-seven thousand, eight hundred ninety-three".