138617840 has 20 divisors (see below), whose sum is σ = 322286664. Its totient is φ = 55447104.

The previous prime is 138617839. The next prime is 138617861. The reversal of 138617840 is 48716831.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 138617794 and 138617803.

It is a congruent number.

It is an unprimeable number.

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, 866282 + ... + 866441.

Almost surely, 2^138617840 is an apocalyptic number.

138617840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138617840 is an abundant number, since it is smaller than the sum of its proper divisors (183668824).

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

138617840 is a wasteful number, since it uses less digits than its factorization.

138617840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1732736 (or 1732730 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 138617840 is about 11773.6077733208. The cubic root of 138617840 is about 517.5349801710.

The spelling of 138617840 in words is "one hundred thirty-eight million, six hundred seventeen thousand, eight hundred forty".