138844840 has 16 divisors (see below), whose sum is σ = 312400980. Its totient is φ = 55537920.

The previous prime is 138844829. The next prime is 138844841. The reversal of 138844840 is 48448831.

It can be written as a sum of positive squares in 2 ways, for example, as 136002244 + 2842596 = 11662^2 + 1686^2 .

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 3471121 = 138844840 / (1 + 3 + 8 + 8 + 4 + 4 + 8 + 4 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 138844793 and 138844802.

It is not an unprimeable number, because it can be changed into a prime (138844841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1735521 + ... + 1735600.

Almost surely, 2^138844840 is an apocalyptic number.

138844840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138844840 is an abundant number, since it is smaller than the sum of its proper divisors (173556140).

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

138844840 is a wasteful number, since it uses less digits than its factorization.

138844840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3471132 (or 3471128 counting only the distinct ones).

The product of its (nonzero) digits is 98304, while the sum is 40.

The square root of 138844840 is about 11783.2440354938. The cubic root of 138844840 is about 517.8173304810.

The spelling of 138844840 in words is "one hundred thirty-eight million, eight hundred forty-four thousand, eight hundred forty".