645503 has 2 divisors, whose sum is σ = 645504. Its totient is φ = 645502.

The previous prime is 645499. The next prime is 645521. The reversal of 645503 is 305546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645503 - 2² = 645499 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645503.

It is not a weakly prime, because it can be changed into another prime (645583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322751 + 322752.

It is an arithmetic number, because the mean of its divisors is an integer number (322752).

2⁶⁴⁵⁵⁰³ is an apocalyptic number.

645503 is a deficient number, since it is larger than the sum of its proper divisors (1).

645503 is an equidigital number, since it uses as much as digits as its factorization.

645503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1800, while the sum is 23.

The square root of 645503 is about 803.4320133029. The cubic root of 645503 is about 86.4236799948.

The spelling of 645503 in words is "six hundred forty-five thousand, five hundred three".