138207857 has 4 divisors (see below), whose sum is σ = 138324900. Its totient is φ = 138090816.

The previous prime is 138207847. The next prime is 138207859. The reversal of 138207857 is 758702831.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 93103201 + 45104656 = 9649^2 + 6716^2 .

It is a cyclic number.

It is not a de Polignac number, because 138207857 - 2⁶ = 138207793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138207859) 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, 56732 + ... + 59117.

It is an arithmetic number, because the mean of its divisors is an integer number (34581225).

Almost surely, 2^138207857 is an apocalyptic number.

It is an amenable number.

138207857 is a deficient number, since it is larger than the sum of its proper divisors (117043).

138207857 is a wasteful number, since it uses less digits than its factorization.

138207857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117042.

The product of its (nonzero) digits is 94080, while the sum is 41.

The square root of 138207857 is about 11756.1837770596. The cubic root of 138207857 is about 517.0242472731.

The spelling of 138207857 in words is "one hundred thirty-eight million, two hundred seven thousand, eight hundred fifty-seven".