138257187 has 4 divisors (see below), whose sum is σ = 184342920. Its totient is φ = 92171456.

The previous prime is 138257177. The next prime is 138257219. The reversal of 138257187 is 781752831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 781752831 = 3 ⋅260584277.

It is a cyclic number.

It is not a de Polignac number, because 138257187 - 2⁷ = 138257059 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138257137) 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, 23042862 + ... + 23042867.

It is an arithmetic number, because the mean of its divisors is an integer number (46085730).

Almost surely, 2^138257187 is an apocalyptic number.

138257187 is a deficient number, since it is larger than the sum of its proper divisors (46085733).

138257187 is an equidigital number, since it uses as much as digits as its factorization.

138257187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46085732.

The product of its digits is 94080, while the sum is 42.

The square root of 138257187 is about 11758.2816346607. The cubic root of 138257187 is about 517.0857531161.

It can be divided in two parts, 13825 and 7187, that added together give a palindrome (21012).

The spelling of 138257187 in words is "one hundred thirty-eight million, two hundred fifty-seven thousand, one hundred eighty-seven".