99166721 has 2 divisors, whose sum is σ = 99166722. Its totient is φ = 99166720.

The previous prime is 99166699. The next prime is 99166723. The reversal of 99166721 is 12766199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 93876721 + 5290000 = 9689^2 + 2300^2 .

It is an emirp because it is prime and its reverse (12766199) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99166721 is a prime.

Together with 99166723, 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 (99166723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49583360 + 49583361.

It is an arithmetic number, because the mean of its divisors is an integer number (49583361).

Almost surely, 2^99166721 is an apocalyptic number.

It is an amenable number.

99166721 is a deficient number, since it is larger than the sum of its proper divisors (1).

99166721 is an equidigital number, since it uses as much as digits as its factorization.

99166721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40824, while the sum is 41.

The square root of 99166721 is about 9958.2488922501. The cubic root of 99166721 is about 462.8660395179.

The spelling of 99166721 in words is "ninety-nine million, one hundred sixty-six thousand, seven hundred twenty-one".