8166509849 has 2 divisors, whose sum is σ = 8166509850. Its totient is φ = 8166509848.

The previous prime is 8166509821. The next prime is 8166509899. The reversal of 8166509849 is 9489056618.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8155354249 + 11155600 = 90307^2 + 3340^2 .

It is a cyclic number.

It is not a de Polignac number, because 8166509849 - 2²⁰ = 8165461273 is a prime.

It is a super-2 number, since 2×8166509849² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 8166509794 and 8166509803.

It is not a weakly prime, because it can be changed into another prime (8166509899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4083254924 + 4083254925.

It is an arithmetic number, because the mean of its divisors is an integer number (4083254925).

Almost surely, 2^8166509849 is an apocalyptic number.

It is an amenable number.

8166509849 is a deficient number, since it is larger than the sum of its proper divisors (1).

8166509849 is an equidigital number, since it uses as much as digits as its factorization.

8166509849 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3732480, while the sum is 56.

The square root of 8166509849 is about 90368.7437613249. The cubic root of 8166509849 is about 2013.7806495135.

The spelling of 8166509849 in words is "eight billion, one hundred sixty-six million, five hundred nine thousand, eight hundred forty-nine".