138836840 has 32 divisors (see below), whose sum is σ = 312861960. Its totient is φ = 55449600.

The previous prime is 138836777. The next prime is 138836843. The reversal of 138836840 is 48638831.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 51638596 + 87198244 = 7186^2 + 9338^2 .

It is a Smith number, since the sum of its digits (41) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (138836843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28160 + ... + 32720.

Almost surely, 2^138836840 is an apocalyptic number.

138836840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138836840 is an abundant number, since it is smaller than the sum of its proper divisors (174025120).

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

138836840 is a wasteful number, since it uses less digits than its factorization.

138836840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5333 (or 5329 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 41.

The square root of 138836840 is about 11782.9045655135. The cubic root of 138836840 is about 517.8073850431.

The spelling of 138836840 in words is "one hundred thirty-eight million, eight hundred thirty-six thousand, eight hundred forty".