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2105809 is a prime number
BaseRepresentation
bin1000000010000111010001
310221222121221
420002013101
51014341214
6113045041
723620246
oct10020721
93858557
102105809
111209142
12856781
13589654
143cb5cd
152b8e24
hex2021d1

2105809 has 2 divisors, whose sum is σ = 2105810. Its totient is φ = 2105808.

The previous prime is 2105767. The next prime is 2105813. The reversal of 2105809 is 9085012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1763584 + 342225 = 1328^2 + 585^2 .

It is a cyclic number.

It is not a de Polignac number, because 2105809 - 27 = 2105681 is a prime.

It is not a weakly prime, because it can be changed into another prime (2105819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1052904 + 1052905.

It is an arithmetic number, because the mean of its divisors is an integer number (1052905).

22105809 is an apocalyptic number.

It is an amenable number.

2105809 is a deficient number, since it is larger than the sum of its proper divisors (1).

2105809 is an equidigital number, since it uses as much as digits as its factorization.

2105809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 2105809 is about 1451.1405858841. The cubic root of 2105809 is about 128.1758853205.

The spelling of 2105809 in words is "two million, one hundred five thousand, eight hundred nine".