138631784 has 8 divisors (see below), whose sum is σ = 259934610. Its totient is φ = 69315888.

The previous prime is 138631781. The next prime is 138631813. The reversal of 138631784 is 487136831.

138631784 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 119464900 + 19166884 = 10930^2 + 4378^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (138631781) 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 as a sum of consecutive naturals, namely, 8664479 + ... + 8664494.

Almost surely, 2^138631784 is an apocalyptic number.

It is an amenable number.

138631784 is a deficient number, since it is larger than the sum of its proper divisors (121302826).

138631784 is a wasteful number, since it uses less digits than its factorization.

138631784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17328979 (or 17328975 counting only the distinct ones).

The product of its digits is 96768, while the sum is 41.

The square root of 138631784 is about 11774.1999303562. The cubic root of 138631784 is about 517.5523330741.

The spelling of 138631784 in words is "one hundred thirty-eight million, six hundred thirty-one thousand, seven hundred eighty-four".