138686581440 has 672 divisors, whose sum is σ = 552897446400. Its totient is φ = 31554109440.

The previous prime is 138686581399. The next prime is 138686581447. The reversal of 138686581440 is 44185686831.

138686581440 is a `hidden beast` number, since 1 + 3 + 8 + 68 + 65 + 81 + 440 = 666.

It is a Smith number, since the sum of its digits (54) 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 (138686581447) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 68015941 + ... + 68017979.

Almost surely, 2^138686581440 is an apocalyptic number.

138686581440 is a gapful number since it is divisible by the number (10) 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 138686581440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (276448723200).

138686581440 is an abundant number, since it is smaller than the sum of its proper divisors (414210864960).

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

138686581440 is a wasteful number, since it uses less digits than its factorization.

138686581440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2205 (or 2192 counting only the distinct ones).

The product of its (nonzero) digits is 4423680, while the sum is 54.

The spelling of 138686581440 in words is "one hundred thirty-eight billion, six hundred eighty-six million, five hundred eighty-one thousand, four hundred forty".