138511758 has 64 divisors (see below), whose sum is σ = 347576832. Its totient is φ = 35748480.

The previous prime is 138511753. The next prime is 138511771. The reversal of 138511758 is 857115831.

It is a happy number.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138511753) 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, 79060 + ... + 80792.

It is an arithmetic number, because the mean of its divisors is an integer number (5430888).

Almost surely, 2^138511758 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138511758, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (173788416).

138511758 is an abundant number, since it is smaller than the sum of its proper divisors (209065074).

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

138511758 is a wasteful number, since it uses less digits than its factorization.

138511758 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1929.

The product of its digits is 33600, while the sum is 39.

The square root of 138511758 is about 11769.1018348895. The cubic root of 138511758 is about 517.4029260845.

The spelling of 138511758 in words is "one hundred thirty-eight million, five hundred eleven thousand, seven hundred fifty-eight".