645441020 has 48 divisors (see below), whose sum is σ = 1630594560. Its totient is φ = 209646144.

The previous prime is 645441011. The next prime is 645441037. The reversal of 645441020 is 20144546.

It is a super-2 number, since 2×645441020² = 833188220597280800, which contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 118664 + ... + 123983.

It is an arithmetic number, because the mean of its divisors is an integer number (33970720).

Almost surely, 2^645441020 is an apocalyptic number.

It is an amenable number.

645441020 is an abundant number, since it is smaller than the sum of its proper divisors (985153540).

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

645441020 is a wasteful number, since it uses less digits than its factorization.

645441020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242682 (or 242680 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

The square root of 645441020 is about 25405.5312874972. The cubic root of 645441020 is about 864.2091382583.

Adding to 645441020 its reverse (20144546), we get a palindrome (665585566).

It can be divided in two parts, 6454 and 41020, that added together give a palindrome (47474).

The spelling of 645441020 in words is "six hundred forty-five million, four hundred forty-one thousand, twenty".