138635658 has 64 divisors (see below), whose sum is σ = 363479040. Its totient is φ = 38329200.

The previous prime is 138635641. The next prime is 138635669. The reversal of 138635658 is 856536831.

138635658 is a `hidden beast` number, since 1 + 3 + 8 + 635 + 6 + 5 + 8 = 666.

It is a Curzon 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 31 ways as a sum of consecutive naturals, for example, 5803 + ... + 17633.

It is an arithmetic number, because the mean of its divisors is an integer number (5679360).

Almost surely, 2^138635658 is an apocalyptic number.

138635658 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 138635658, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (181739520).

138635658 is an abundant number, since it is smaller than the sum of its proper divisors (224843382).

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

138635658 is a wasteful number, since it uses less digits than its factorization.

138635658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11880 (or 11874 counting only the distinct ones).

The product of its digits is 518400, while the sum is 45.

The square root of 138635658 is about 11774.3644414465. The cubic root of 138635658 is about 517.5571539480.

The spelling of 138635658 in words is "one hundred thirty-eight million, six hundred thirty-five thousand, six hundred fifty-eight".