138645504 has 78 divisors (see below), whose sum is σ = 400589046. Its totient is φ = 46202880.

The previous prime is 138645503. The next prime is 138645511. The reversal of 138645504 is 405546831.

It is a happy number.

138645504 is a `hidden beast` number, since 1 + 3 + 8 + 645 + 5 + 0 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 115605504 + 23040000 = 10752^2 + 4800^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138645503) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 34984 + ... + 38744.

It is an arithmetic number, because the mean of its divisors is an integer number (5135757).

Almost surely, 2^138645504 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138645504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (200294523).

138645504 is an abundant number, since it is smaller than the sum of its proper divisors (261943542).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138645504 is an equidigital number, since it uses as much as digits as its factorization.

138645504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3791 (or 3766 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 138645504 is about 11774.7825457628. The cubic root of 138645504 is about 517.5694060799.

The spelling of 138645504 in words is "one hundred thirty-eight million, six hundred forty-five thousand, five hundred four".