138819636 has 96 divisors (see below), whose sum is σ = 376320000. Its totient is φ = 44198784.

The previous prime is 138819631. The next prime is 138819641. The reversal of 138819636 is 636918831.

It is a happy number.

138819636 is a `hidden beast` number, since 1 + 3 + 8 + 8 + 1 + 9 + 636 = 666.

It is an interprime number because it is at equal distance from previous prime (138819631) and next prime (138819641).

It is a junction number, because it is equal to n+sod(n) for n = 138819591 and 138819600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138819631) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 397590 + ... + 397938.

It is an arithmetic number, because the mean of its divisors is an integer number (3920000).

Almost surely, 2^138819636 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 138819636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (188160000).

138819636 is an abundant number, since it is smaller than the sum of its proper divisors (237500364).

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

138819636 is a wasteful number, since it uses less digits than its factorization.

138819636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518 (or 510 counting only the distinct ones).

The product of its digits is 186624, while the sum is 45.

The square root of 138819636 is about 11782.1745021876. The cubic root of 138819636 is about 517.7859960846.

The spelling of 138819636 in words is "one hundred thirty-eight million, eight hundred nineteen thousand, six hundred thirty-six".