645020 has 12 divisors (see below), whose sum is σ = 1354584. Its totient is φ = 258000.

The previous prime is 645019. The next prime is 645023. The reversal of 645020 is 20546.

It is a self number, because there is not a number n which added to its sum of digits gives 645020.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16106 + ... + 16145.

It is an arithmetic number, because the mean of its divisors is an integer number (112882).

2⁶⁴⁵⁰²⁰ is an apocalyptic number.

It is an amenable number.

645020 is an abundant number, since it is smaller than the sum of its proper divisors (709564).

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

645020 is a wasteful number, since it uses less digits than its factorization.

645020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32260 (or 32258 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 645020 is about 803.1313715701. The cubic root of 645020 is about 86.4021190038.

Adding to 645020 its reverse (20546), we get a palindrome (665566).

The spelling of 645020 in words is "six hundred forty-five thousand, twenty".