999802109 has 2 divisors, whose sum is σ = 999802110. Its totient is φ = 999802108.

The previous prime is 999802099. The next prime is 999802121. The reversal of 999802109 is 901208999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 850888900 + 148913209 = 29170^2 + 12203^2 .

It is an emirp because it is prime and its reverse (901208999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999802109 - 2⁸ = 999801853 is a prime.

It is a super-3 number, since 3×999802109³ (a number of 28 digits) contains 333 as substring.

It is equal to p_50837969 and since 999802109 and 50837969 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999802169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499901054 + 499901055.

It is an arithmetic number, because the mean of its divisors is an integer number (499901055).

Almost surely, 2^999802109 is an apocalyptic number.

It is an amenable number.

999802109 is a deficient number, since it is larger than the sum of its proper divisors (1).

999802109 is an equidigital number, since it uses as much as digits as its factorization.

999802109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 47.

The square root of 999802109 is about 31619.6475154294. The cubic root of 999802109 is about 999.9340319816.

The spelling of 999802109 in words is "nine hundred ninety-nine million, eight hundred two thousand, one hundred nine".