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999689681 is a prime number
BaseRepresentation
bin111011100101100…
…000110111010001
32120200002111102202
4323211200313101
54021410032211
6243110452545
733526136114
oct7345406721
92520074382
10999689681
11473331721
1223a964155
1312c15bb73
1496aaa57b
155cb6e53b
hex3b960dd1

999689681 has 2 divisors, whose sum is σ = 999689682. Its totient is φ = 999689680.

The previous prime is 999689629. The next prime is 999689683. The reversal of 999689681 is 186986999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 955799056 + 43890625 = 30916^2 + 6625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-999689681 is a prime.

It is a super-2 number, since 2×9996896812 = 1998758916595763522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 999689683, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (999689683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499844840 + 499844841.

It is an arithmetic number, because the mean of its divisors is an integer number (499844841).

Almost surely, 2999689681 is an apocalyptic number.

It is an amenable number.

999689681 is a deficient number, since it is larger than the sum of its proper divisors (1).

999689681 is an equidigital number, since it uses as much as digits as its factorization.

999689681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15116544, while the sum is 65.

The square root of 999689681 is about 31617.8696467678. The cubic root of 999689681 is about 999.8965496317.

The spelling of 999689681 in words is "nine hundred ninety-nine million, six hundred eighty-nine thousand, six hundred eighty-one".