138579840 has 288 divisors, whose sum is σ = 557795160. Its totient is φ = 31610880.

The previous prime is 138579823. The next prime is 138579851. The reversal of 138579840 is 48975831.

138579840 is a `hidden beast` number, since 1 + 38 + 579 + 8 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 281995 + ... + 282485.

Almost surely, 2^138579840 is an apocalyptic number.

138579840 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 138579840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (278897580).

138579840 is an abundant number, since it is smaller than the sum of its proper divisors (419215320).

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

138579840 is a wasteful number, since it uses less digits than its factorization.

138579840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530 (or 508 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 138579840 is about 11771.9938837905. The cubic root of 138579840 is about 517.4876843670.

It can be divided in two parts, 1385 and 79840, that added together give a square (81225 = 285²).

The spelling of 138579840 in words is "one hundred thirty-eight million, five hundred seventy-nine thousand, eight hundred forty".