138658240 has 168 divisors, whose sum is σ = 396118080. Its totient is φ = 46061568.

The previous prime is 138658231. The next prime is 138658241. The reversal of 138658240 is 42856831.

It is a happy number.

It is a super-2 number, since 2×138658240² = 38452215039795200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a self number, because there is not a number n which added to its sum of digits gives 138658240.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138658241) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 580041 + ... + 580279.

Almost surely, 2^138658240 is an apocalyptic number.

138658240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138658240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (198059040).

138658240 is an abundant number, since it is smaller than the sum of its proper divisors (257459840).

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

138658240 is a wasteful number, since it uses less digits than its factorization.

138658240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307 (or 290 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 37.

The square root of 138658240 is about 11775.3233501250. The cubic root of 138658240 is about 517.5852535997.

It can be divided in two parts, 138 and 658240, that added together give a triangular number (658378 = T₁₁₄₇).

The spelling of 138658240 in words is "one hundred thirty-eight million, six hundred fifty-eight thousand, two hundred forty".