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BaseRepresentation
bin10011100010010101
311001202202
4103202111
510030041
61414245
7452204
oct234225
9131682
1080021
1155137
123a385
132a566
142123b
1518a9b
hex13895

80021 has 2 divisors, whose sum is σ = 80022. Its totient is φ = 80020.

The previous prime is 79999. The next prime is 80039. The reversal of 80021 is 12008.

Adding to 80021 its reverse (12008), we get a palindrome (92029).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45796 + 34225 = 214^2 + 185^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-80021 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 79984 and 80011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40010 + 40011.

It is an arithmetic number, because the mean of its divisors is an integer number (40011).

280021 is an apocalyptic number.

It is an amenable number.

80021 is a deficient number, since it is larger than the sum of its proper divisors (1).

80021 is an equidigital number, since it uses as much as digits as its factorization.

80021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 80021 is about 282.8798331447. The cubic root of 80021 is about 43.0924637315.

The spelling of 80021 in words is "eighty thousand, twenty-one".