128780 has 24 divisors (see below), whose sum is σ = 278208. Its totient is φ = 50048.
The previous prime is 128767. The next prime is 128813. The reversal of 128780 is 87821.
It is a nialpdrome in base 11.
It is a zygodrome in base 11.
It is an unprimeable number.
128780 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 872 + ... + 1008.
It is an arithmetic number, because the mean of its divisors is an integer number (11592).
2128780 is an apocalyptic number.
128780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.
It is an amenable number.
128780 is an abundant number, since it is smaller than the sum of its proper divisors (149428).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
128780 is a wasteful number, since it uses less digits than its factorization.
128780 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 193 (or 191 counting only the distinct ones).
The product of its (nonzero) digits is 896, while the sum is 26.
The square root of 128780 is about 358.8593039061. The cubic root of 128780 is about 50.4990033460.
The spelling of 128780 in words is "one hundred twenty-eight thousand, seven hundred eighty".
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