645650 has 24 divisors (see below), whose sum is σ = 1236900. Its totient is φ = 250560.

The previous prime is 645649. The next prime is 645661. The reversal of 645650 is 56546.

645650 is nontrivially palindromic in base 7.

It can be written as a sum of positive squares in 6 ways, for example, as 452929 + 192721 = 673^2 + 439^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1676 + ... + 2024.

2⁶⁴⁵⁶⁵⁰ is an apocalyptic number.

645650 is a deficient number, since it is larger than the sum of its proper divisors (591250).

645650 is a wasteful number, since it uses less digits than its factorization.

645650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398 (or 393 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 645650 is about 803.5234906336. The cubic root of 645650 is about 86.4302399007.

The spelling of 645650 in words is "six hundred forty-five thousand, six hundred fifty".