138243456 has 256 divisors, whose sum is σ = 467812800. Its totient is φ = 39813120.

The previous prime is 138243421. The next prime is 138243481. The reversal of 138243456 is 654342831.

It is a super-2 number, since 2×138243456² = 38222506253647872, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

Its product of digits (69120) is a multiple of the sum of its prime divisors (216).

It is a self number, because there is not a number n which added to its sum of digits gives 138243456.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 763686 + ... + 763866.

Almost surely, 2^138243456 is an apocalyptic number.

138243456 is a gapful number since it is divisible by the number (16) 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 138243456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (233906400).

138243456 is an abundant number, since it is smaller than the sum of its proper divisors (329569344).

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

138243456 is a wasteful number, since it uses less digits than its factorization.

138243456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234 (or 216 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 138243456 is about 11757.6977338253. The cubic root of 138243456 is about 517.0686344411.

It can be divided in two parts, 13824 and 3456, that multiplied together give a square (47775744 = 6912²).

The spelling of 138243456 in words is "one hundred thirty-eight million, two hundred forty-three thousand, four hundred fifty-six".