138511968 has 192 divisors, whose sum is σ = 439971840. Its totient is φ = 37324800.

The previous prime is 138511927. The next prime is 138511969. The reversal of 138511968 is 869115831.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138511969) 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, 1270698 + ... + 1270806.

It is an arithmetic number, because the mean of its divisors is an integer number (2291520).

Almost surely, 2^138511968 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 138511968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (219985920).

138511968 is an abundant number, since it is smaller than the sum of its proper divisors (301459872).

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

138511968 is a wasteful number, since it uses less digits than its factorization.

138511968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221 (or 213 counting only the distinct ones).

The product of its digits is 51840, while the sum is 42.

The square root of 138511968 is about 11769.1107565525. The cubic root of 138511968 is about 517.4031875655.

The spelling of 138511968 in words is "one hundred thirty-eight million, five hundred eleven thousand, nine hundred sixty-eight".