3985815209 has 2 divisors, whose sum is σ = 3985815210. Its totient is φ = 3985815208.

The previous prime is 3985815191. The next prime is 3985815227. The reversal of 3985815209 is 9025185893.

It is a balanced prime because it is at equal distance from previous prime (3985815191) and next prime (3985815227).

It can be written as a sum of positive squares in only one way, i.e., 2042768809 + 1943046400 = 45197^2 + 44080^2 .

It is a cyclic number.

It is not a de Polignac number, because 3985815209 - 2²⁴ = 3969037993 is a prime.

It is not a weakly prime, because it can be changed into another prime (3985815259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1992907604 + 1992907605.

It is an arithmetic number, because the mean of its divisors is an integer number (1992907605).

Almost surely, 2^3985815209 is an apocalyptic number.

It is an amenable number.

3985815209 is a deficient number, since it is larger than the sum of its proper divisors (1).

3985815209 is an equidigital number, since it uses as much as digits as its factorization.

3985815209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 777600, while the sum is 50.

The square root of 3985815209 is about 63133.3129892611. The cubic root of 3985815209 is about 1585.5224168650.

The spelling of 3985815209 in words is "three billion, nine hundred eighty-five million, eight hundred fifteen thousand, two hundred nine".