645000509 has 2 divisors, whose sum is σ = 645000510. Its totient is φ = 645000508.

The previous prime is 645000487. The next prime is 645000527. The reversal of 645000509 is 905000546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 618765625 + 26234884 = 24875^2 + 5122^2 .

It is a cyclic number.

It is not a de Polignac number, because 645000509 - 2⁸ = 645000253 is a prime.

It is a super-2 number, since 2×645000509² = 832051313220518162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645000589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322500254 + 322500255.

It is an arithmetic number, because the mean of its divisors is an integer number (322500255).

Almost surely, 2^645000509 is an apocalyptic number.

It is an amenable number.

645000509 is a deficient number, since it is larger than the sum of its proper divisors (1).

645000509 is an equidigital number, since it uses as much as digits as its factorization.

645000509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 645000509 is about 25396.8602193263. The cubic root of 645000509 is about 864.0124870488.

The spelling of 645000509 in words is "six hundred forty-five million, five hundred nine", and thus it is an aban number.