138256240 has 80 divisors (see below), whose sum is σ = 342513792. Its totient is φ = 51720192.

The previous prime is 138256229. The next prime is 138256267. The reversal of 138256240 is 42652831.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×138256240² = 38229575797875200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 376537 + ... + 376903.

Almost surely, 2^138256240 is an apocalyptic number.

138256240 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 138256240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171256896).

138256240 is an abundant number, since it is smaller than the sum of its proper divisors (204257552).

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

138256240 is a wasteful number, since it uses less digits than its factorization.

138256240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 674 (or 668 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 138256240 is about 11758.2413651022. The cubic root of 138256240 is about 517.0845725112.

The spelling of 138256240 in words is "one hundred thirty-eight million, two hundred fifty-six thousand, two hundred forty".