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128521 is a prime number
BaseRepresentation
bin11111011000001001
320112022001
4133120021
513103041
62431001
71043461
oct373011
9215261
10128521
1188618
1262461
1346663
1434ba1
1528131
hex1f609

128521 has 2 divisors, whose sum is σ = 128522. Its totient is φ = 128520.

The previous prime is 128519. The next prime is 128549. The reversal of 128521 is 125821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112896 + 15625 = 336^2 + 125^2 .

It is an emirp because it is prime and its reverse (125821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128521 - 21 = 128519 is a prime.

Together with 128519, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (128551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64260 + 64261.

It is an arithmetic number, because the mean of its divisors is an integer number (64261).

2128521 is an apocalyptic number.

It is an amenable number.

128521 is a deficient number, since it is larger than the sum of its proper divisors (1).

128521 is an equidigital number, since it uses as much as digits as its factorization.

128521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 160, while the sum is 19.

The square root of 128521 is about 358.4982566206. The cubic root of 128521 is about 50.4651263985.

The spelling of 128521 in words is "one hundred twenty-eight thousand, five hundred twenty-one".