389987809 has 2 divisors, whose sum is σ = 389987810. Its totient is φ = 389987808.

The previous prime is 389987797. The next prime is 389987831. The reversal of 389987809 is 908789983.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 254498209 + 135489600 = 15953^2 + 11640^2 .

It is an emirp because it is prime and its reverse (908789983) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-389987809 is a prime.

It is not a weakly prime, because it can be changed into another prime (389987869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 194993904 + 194993905.

It is an arithmetic number, because the mean of its divisors is an integer number (194993905).

Almost surely, 2^389987809 is an apocalyptic number.

It is an amenable number.

389987809 is a deficient number, since it is larger than the sum of its proper divisors (1).

389987809 is an equidigital number, since it uses as much as digits as its factorization.

389987809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7838208, while the sum is 61.

The square root of 389987809 is about 19748.1089980788. The cubic root of 389987809 is about 730.6067445751.

The spelling of 389987809 in words is "three hundred eighty-nine million, nine hundred eighty-seven thousand, eight hundred nine".