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138257280 = 273557127

138257280 has 384 divisors, whose sum is σ = 570286080. Its totient is φ = 31352832.

The previous prime is 138257263. The next prime is 138257321. The reversal of 138257280 is 82752831.

138257280 is a `hidden beast` number, since 1 + 3 + 8 + 2 + 572 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-4 number, since 4×1382572804 (a number of 34 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1088577 + ... + 1088703.

It is an arithmetic number, because the mean of its divisors is an integer number (1485120).

Almost surely, 2138257280 is an apocalyptic number.

138257280 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 138257280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (285143040).

138257280 is an abundant number, since it is smaller than the sum of its proper divisors (432028800).

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

138257280 is an equidigital number, since it uses as much as digits as its factorization.

138257280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168 (or 144 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 138257280 is about 11758.2855893196. The cubic root of 138257280 is about 517.0858690569.

The spelling of 138257280 in words is "one hundred thirty-eight million, two hundred fifty-seven thousand, two hundred eighty".