645524020 has 12 divisors (see below), whose sum is σ = 1355600484. Its totient is φ = 258209600.

The previous prime is 645523997. The next prime is 645524053. The reversal of 645524020 is 20425546.

It can be written as a sum of positive squares in 2 ways, for example, as 98525476 + 546998544 = 9926^2 + 23388^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 645524020.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16138081 + ... + 16138120.

It is an arithmetic number, because the mean of its divisors is an integer number (112966707).

Almost surely, 2^645524020 is an apocalyptic number.

It is an amenable number.

645524020 is an abundant number, since it is smaller than the sum of its proper divisors (710076464).

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

645524020 is a wasteful number, since it uses less digits than its factorization.

645524020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32276210 (or 32276208 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 28.

The square root of 645524020 is about 25407.1647375302. The cubic root of 645524020 is about 864.2461807775.

Adding to 645524020 its reverse (20425546), we get a palindrome (665949566).

The spelling of 645524020 in words is "six hundred forty-five million, five hundred twenty-four thousand, twenty".