138571777 has 4 divisors (see below), whose sum is σ = 146723076. Its totient is φ = 130420480.

The previous prime is 138571751. The next prime is 138571781. The reversal of 138571777 is 777175831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 777175831 = 17551 ⋅44281.

It can be written as a sum of positive squares in 2 ways, for example, as 130051216 + 8520561 = 11404^2 + 2919^2 .

It is a cyclic number.

It is not a de Polignac number, because 138571777 - 2⁷ = 138571649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138571717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4075624 + ... + 4075657.

It is an arithmetic number, because the mean of its divisors is an integer number (36680769).

Almost surely, 2^138571777 is an apocalyptic number.

138571777 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

138571777 is a deficient number, since it is larger than the sum of its proper divisors (8151299).

138571777 is an equidigital number, since it uses as much as digits as its factorization.

138571777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8151298.

The product of its digits is 288120, while the sum is 46.

The square root of 138571777 is about 11771.6514134594. The cubic root of 138571777 is about 517.4776478323.

It can be divided in two parts, 138 and 571777, that added together give a triangular number (571915 = T₁₀₆₉).

The spelling of 138571777 in words is "one hundred thirty-eight million, five hundred seventy-one thousand, seven hundred seventy-seven".