509581021 has 2 divisors, whose sum is σ = 509581022. Its totient is φ = 509581020.

The previous prime is 509581013. The next prime is 509581063. The reversal of 509581021 is 120185905.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 296012025 + 213568996 = 17205^2 + 14614^2 .

It is a cyclic number.

It is not a de Polignac number, because 509581021 - 2³ = 509581013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (509581421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 254790510 + 254790511.

It is an arithmetic number, because the mean of its divisors is an integer number (254790511).

Almost surely, 2^509581021 is an apocalyptic number.

It is an amenable number.

509581021 is a deficient number, since it is larger than the sum of its proper divisors (1).

509581021 is an equidigital number, since it uses as much as digits as its factorization.

509581021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3600, while the sum is 31.

The square root of 509581021 is about 22573.9013243170. The cubic root of 509581021 is about 798.7381257424.

The spelling of 509581021 in words is "five hundred nine million, five hundred eighty-one thousand, twenty-one".