645499 has 2 divisors, whose sum is σ = 645500. Its totient is φ = 645498.

The previous prime is 645497. The next prime is 645503. The reversal of 645499 is 994546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645499 - 2¹ = 645497 is a prime.

Together with 645497, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (645493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322749 + 322750.

It is an arithmetic number, because the mean of its divisors is an integer number (322750).

2⁶⁴⁵⁴⁹⁹ is an apocalyptic number.

645499 is a deficient number, since it is larger than the sum of its proper divisors (1).

645499 is an equidigital number, since it uses as much as digits as its factorization.

645499 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 37.

The square root of 645499 is about 803.4295239783. The cubic root of 645499 is about 86.4235014801.

The spelling of 645499 in words is "six hundred forty-five thousand, four hundred ninety-nine".