39845621209 has 2 divisors, whose sum is σ = 39845621210. Its totient is φ = 39845621208.

The previous prime is 39845621203. The next prime is 39845621269. The reversal of 39845621209 is 90212654893.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21396375625 + 18449245584 = 146275^2 + 135828^2 .

It is a cyclic number.

It is not a de Polignac number, because 39845621209 - 2¹¹ = 39845619161 is a prime.

It is a super-2 number, since 2×39845621209² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (39845621203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19922810604 + 19922810605.

It is an arithmetic number, because the mean of its divisors is an integer number (19922810605).

Almost surely, 2^39845621209 is an apocalyptic number.

It is an amenable number.

39845621209 is a deficient number, since it is larger than the sum of its proper divisors (1).

39845621209 is an equidigital number, since it uses as much as digits as its factorization.

39845621209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 933120, while the sum is 49.

The spelling of 39845621209 in words is "thirty-nine billion, eight hundred forty-five million, six hundred twenty-one thousand, two hundred nine".