138187491 has 16 divisors (see below), whose sum is σ = 204825600. Its totient is φ = 82294560.

The previous prime is 138187481. The next prime is 138187501. The reversal of 138187491 is 194781831.

It is an interprime number because it is at equal distance from previous prime (138187481) and next prime (138187501).

It is not a de Polignac number, because 138187491 - 2⁵ = 138187459 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138187411) 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 15 ways as a sum of consecutive naturals, for example, 55941 + ... + 58358.

It is an arithmetic number, because the mean of its divisors is an integer number (12801600).

Almost surely, 2^138187491 is an apocalyptic number.

138187491 is a deficient number, since it is larger than the sum of its proper divisors (66638109).

138187491 is a wasteful number, since it uses less digits than its factorization.

138187491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114346.

The product of its digits is 48384, while the sum is 42.

The square root of 138187491 is about 11755.3175627033. The cubic root of 138187491 is about 516.9988501808.

The spelling of 138187491 in words is "one hundred thirty-eight million, one hundred eighty-seven thousand, four hundred ninety-one".