645170020 has 24 divisors (see below), whose sum is σ = 1478026368. Its totient is φ = 234607200.

The previous prime is 645170003. The next prime is 645170021. The reversal of 645170020 is 20071546.

It is not an unprimeable number, because it can be changed into a prime (645170021) 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 in 7 ways as a sum of consecutive naturals, for example, 1466076 + ... + 1466515.

It is an arithmetic number, because the mean of its divisors is an integer number (61584432).

Almost surely, 2^645170020 is an apocalyptic number.

It is an amenable number.

645170020 is an abundant number, since it is smaller than the sum of its proper divisors (832856348).

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

645170020 is a wasteful number, since it uses less digits than its factorization.

645170020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2932611 (or 2932609 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 645170020 is about 25400.1972433286. The cubic root of 645170020 is about 864.0881700858.

The spelling of 645170020 in words is "six hundred forty-five million, one hundred seventy thousand, twenty".