509489891 has 2 divisors, whose sum is σ = 509489892. Its totient is φ = 509489890.

The previous prime is 509489879. The next prime is 509489899. The reversal of 509489891 is 198984905.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 509489891 - 2¹⁰ = 509488867 is a prime.

It is not a weakly prime, because it can be changed into another prime (509489899) 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, 254744945 + 254744946.

It is an arithmetic number, because the mean of its divisors is an integer number (254744946).

Almost surely, 2^509489891 is an apocalyptic number.

509489891 is a deficient number, since it is larger than the sum of its proper divisors (1).

509489891 is an equidigital number, since it uses as much as digits as its factorization.

509489891 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 53.

The square root of 509489891 is about 22571.8827526638. The cubic root of 509489891 is about 798.6905092746.

The spelling of 509489891 in words is "five hundred nine million, four hundred eighty-nine thousand, eight hundred ninety-one".