138163644 has 120 divisors (see below), whose sum is σ = 379239168. Its totient is φ = 43817760.

The previous prime is 138163639. The next prime is 138163651. The reversal of 138163644 is 446361831.

It is a happy number.

138163644 is a `hidden beast` number, since 1 + 3 + 8 + 1 + 6 + 3 + 644 = 666.

138163644 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a junction number, because it is equal to n+sod(n) for n = 138163599 and 138163608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 654699 + ... + 654909.

Almost surely, 2^138163644 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 138163644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189619584).

138163644 is an abundant number, since it is smaller than the sum of its proper divisors (241075524).

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

138163644 is a wasteful number, since it uses less digits than its factorization.

138163644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317 (or 306 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 138163644 is about 11754.3032120156. The cubic root of 138163644 is about 516.9691089919.

It can be divided in two parts, 1381 and 63644, that added together give a square (65025 = 255²).

The spelling of 138163644 in words is "one hundred thirty-eight million, one hundred sixty-three thousand, six hundred forty-four".