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BaseRepresentation
bin100001111010000000
321001111201
4201322000
513421010
62550544
71115620
oct417200
9231451
10138880
1195385
1268454
134b2a1
1438880
152b23a
hex21e80

138880 has 64 divisors (see below), whose sum is σ = 391680. Its totient is φ = 46080.

The previous prime is 138869. The next prime is 138883. The reversal of 138880 is 88831.

It can be divided in two parts, 13 and 8880, that multiplied together give a triangular number (115440 = T480).

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4465 + ... + 4495.

It is an arithmetic number, because the mean of its divisors is an integer number (6120).

2138880 is an apocalyptic number.

138880 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 138880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (195840).

138880 is an abundant number, since it is smaller than the sum of its proper divisors (252800).

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

138880 is an equidigital number, since it uses as much as digits as its factorization.

138880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57 (or 45 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 138880 is about 372.6660703633. Note that the first 3 decimals coincide. The cubic root of 138880 is about 51.7861036152.

The spelling of 138880 in words is "one hundred thirty-eight thousand, eight hundred eighty".