645600020440 has 32 divisors (see below), whose sum is σ = 1452795462000. Its totient is φ = 258205267584.

The previous prime is 645600020423. The next prime is 645600020453. The reversal of 645600020440 is 44020006546.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 783555 + ... + 1380274.

Almost surely, 2^645600020440 is an apocalyptic number.

It is an amenable number.

645600020440 is an abundant number, since it is smaller than the sum of its proper divisors (807195441560).

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

645600020440 is a wasteful number, since it uses less digits than its factorization.

645600020440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2171299 (or 2171295 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 31.

Adding to 645600020440 its reverse (44020006546), we get a palindrome (689620026986).

The spelling of 645600020440 in words is "six hundred forty-five billion, six hundred million, twenty thousand, four hundred forty".