82117920109 has 2 divisors, whose sum is σ = 82117920110. Its totient is φ = 82117920108.

The previous prime is 82117920047. The next prime is 82117920121. The reversal of 82117920109 is 90102971128.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65600015625 + 16517904484 = 256125^2 + 128522^2 .

It is a cyclic number.

It is not a de Polignac number, because 82117920109 - 2¹⁷ = 82117789037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (82117927109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41058960054 + 41058960055.

It is an arithmetic number, because the mean of its divisors is an integer number (41058960055).

Almost surely, 2^82117920109 is an apocalyptic number.

It is an amenable number.

82117920109 is a deficient number, since it is larger than the sum of its proper divisors (1).

82117920109 is an equidigital number, since it uses as much as digits as its factorization.

82117920109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 40.

The spelling of 82117920109 in words is "eighty-two billion, one hundred seventeen million, nine hundred twenty thousand, one hundred nine".