138678806640 has 640 divisors, whose sum is σ = 506180459520. Its totient is φ = 31313018880.

The previous prime is 138678806633. The next prime is 138678806663. The reversal of 138678806640 is 46608876831.

It is a super-2 number, since 2×138678806640² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 443063124 + ... + 443063436.

It is an arithmetic number, because the mean of its divisors is an integer number (790906968).

Almost surely, 2^138678806640 is an apocalyptic number.

138678806640 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 138678806640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (253090229760).

138678806640 is an abundant number, since it is smaller than the sum of its proper divisors (367501652880).

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

138678806640 is a wasteful number, since it uses less digits than its factorization.

138678806640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454 (or 426 counting only the distinct ones).

The product of its (nonzero) digits is 9289728, while the sum is 57.

The spelling of 138678806640 in words is "one hundred thirty-eight billion, six hundred seventy-eight million, eight hundred six thousand, six hundred forty".