138679840 has 96 divisors (see below), whose sum is σ = 358945776. Its totient is φ = 50319360.

The previous prime is 138679837. The next prime is 138679843. The reversal of 138679840 is 48976831.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (138679837) and next prime (138679843).

It can be written as a sum of positive squares in 8 ways, for example, as 37797904 + 100881936 = 6148^2 + 10044^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138679843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 126334 + ... + 127426.

Almost surely, 2^138679840 is an apocalyptic number.

138679840 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 138679840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179472888).

138679840 is an abundant number, since it is smaller than the sum of its proper divisors (220265936).

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

138679840 is a wasteful number, since it uses less digits than its factorization.

138679840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1182 (or 1174 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 46.

The square root of 138679840 is about 11776.2404866749. The cubic root of 138679840 is about 517.6121284565.

The spelling of 138679840 in words is "one hundred thirty-eight million, six hundred seventy-nine thousand, eight hundred forty".