138648636 has 108 divisors (see below), whose sum is σ = 415665432. Its totient is φ = 38840256.

The previous prime is 138648589. The next prime is 138648667. The reversal of 138648636 is 636846831.

138648636 is a `hidden beast` number, since 1 + 3 + 8 + 6 + 4 + 8 + 636 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 138648591 and 138648600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 92751 + ... + 94233.

It is an arithmetic number, because the mean of its divisors is an integer number (3848754).

Almost surely, 2^138648636 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 138648636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (207832716).

138648636 is an abundant number, since it is smaller than the sum of its proper divisors (277016796).

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

138648636 is a wasteful number, since it uses less digits than its factorization.

138648636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1560 (or 1548 counting only the distinct ones).

The product of its digits is 497664, while the sum is 45.

The square root of 138648636 is about 11774.9155410984. The cubic root of 138648636 is about 517.5733033458.

It can be divided in two parts, 13864 and 8636, that added together give a square (22500 = 150²).

The spelling of 138648636 in words is "one hundred thirty-eight million, six hundred forty-eight thousand, six hundred thirty-six".