391530989 has 2 divisors, whose sum is σ = 391530990. Its totient is φ = 391530988.

The previous prime is 391530983. The next prime is 391531027. The reversal of 391530989 is 989035193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 197402500 + 194128489 = 14050^2 + 13933^2 .

It is a cyclic number.

It is not a de Polignac number, because 391530989 - 2¹⁶ = 391465453 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391530983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195765494 + 195765495.

It is an arithmetic number, because the mean of its divisors is an integer number (195765495).

Almost surely, 2^391530989 is an apocalyptic number.

It is an amenable number.

391530989 is a deficient number, since it is larger than the sum of its proper divisors (1).

391530989 is an equidigital number, since it uses as much as digits as its factorization.

391530989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 262440, while the sum is 47.

The square root of 391530989 is about 19787.1420119228. The cubic root of 391530989 is about 731.5691454807.

The spelling of 391530989 in words is "three hundred ninety-one million, five hundred thirty thousand, nine hundred eighty-nine".