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19131809 is a prime number
BaseRepresentation
bin100100011111…
…0110110100001
31022222222220112
41020332312201
514344204214
61522021105
7321421604
oct110766641
938888815
1019131809
11a888014
1264a7795
133c6b1c8
14278033b
151a2da3e
hex123eda1

19131809 has 2 divisors, whose sum is σ = 19131810. Its totient is φ = 19131808.

The previous prime is 19131779. The next prime is 19131811. The reversal of 19131809 is 90813191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16224784 + 2907025 = 4028^2 + 1705^2 .

It is a cyclic number.

It is not a de Polignac number, because 19131809 - 224 = 2354593 is a prime.

It is a super-2 number, since 2×191318092 = 732052231224962, which contains 22 as substring.

Together with 19131811, 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 (19131859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9565904 + 9565905.

It is an arithmetic number, because the mean of its divisors is an integer number (9565905).

Almost surely, 219131809 is an apocalyptic number.

It is an amenable number.

19131809 is a deficient number, since it is larger than the sum of its proper divisors (1).

19131809 is an equidigital number, since it uses as much as digits as its factorization.

19131809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 32.

The square root of 19131809 is about 4373.9923410998. The cubic root of 19131809 is about 267.4557949489.

The spelling of 19131809 in words is "nineteen million, one hundred thirty-one thousand, eight hundred nine".