645930 has 24 divisors (see below), whose sum is σ = 1679652. Its totient is φ = 172224.

The previous prime is 645907. The next prime is 645937. The reversal of 645930 is 39546.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 622521 + 23409 = 789^2 + 153^2 .

It is an Ulam number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 645894 and 645903.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645930.

It is not an unprimeable number, because it can be changed into a prime (645937) by changing a digit.

645930 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3499 + ... + 3678.

2⁶⁴⁵⁹³⁰ is an apocalyptic number.

645930 is an abundant number, since it is smaller than the sum of its proper divisors (1033722).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645930 is a wasteful number, since it uses less digits than its factorization.

645930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7190 (or 7187 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 645930 is about 803.6977043640. The cubic root of 645930 is about 86.4427322054.

The spelling of 645930 in words is "six hundred forty-five thousand, nine hundred thirty".