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99721 is a prime number
BaseRepresentation
bin11000010110001001
312001210101
4120112021
511142341
62045401
7563506
oct302611
9161711
1099721
1168a16
1249861
133650b
14284ad
151e831
hex18589

99721 has 2 divisors, whose sum is σ = 99722. Its totient is φ = 99720.

The previous prime is 99719. The next prime is 99733. The reversal of 99721 is 12799.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81225 + 18496 = 285^2 + 136^2 .

It is an emirp because it is prime and its reverse (12799) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99721 - 21 = 99719 is a prime.

Together with 99719, it forms a pair of twin primes.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 99721.

It is not a weakly prime, because it can be changed into another prime (99761) 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, 49860 + 49861.

It is an arithmetic number, because the mean of its divisors is an integer number (49861).

299721 is an apocalyptic number.

It is an amenable number.

99721 is a deficient number, since it is larger than the sum of its proper divisors (1).

99721 is an equidigital number, since it uses as much as digits as its factorization.

99721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1134, while the sum is 28.

The square root of 99721 is about 315.7863201597. The cubic root of 99721 is about 46.3726813525.

It can be divided in two parts, 99 and 721, that added together give a triangular number (820 = T40).

The spelling of 99721 in words is "ninety-nine thousand, seven hundred twenty-one".