509145721 has 12 divisors (see below), whose sum is σ = 612696420. Its totient is φ = 421360800.

The previous prime is 509145709. The next prime is 509145739. The reversal of 509145721 is 127541905.

It can be written as a sum of positive squares in 2 ways, for example, as 370023696 + 139122025 = 19236^2 + 11795^2 .

It is not a de Polignac number, because 509145721 - 2¹³ = 509137529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (509145701) 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 in 11 ways as a sum of consecutive naturals, for example, 177730 + ... + 180571.

It is an arithmetic number, because the mean of its divisors is an integer number (51058035).

Almost surely, 2^509145721 is an apocalyptic number.

It is an amenable number.

509145721 is a deficient number, since it is larger than the sum of its proper divisors (103550699).

509145721 is a wasteful number, since it uses less digits than its factorization.

509145721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358344 (or 358337 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 34.

The square root of 509145721 is about 22564.2575991323. The cubic root of 509145721 is about 798.5106252786.

The spelling of 509145721 in words is "five hundred nine million, one hundred forty-five thousand, seven hundred twenty-one".