645545544 has 64 divisors (see below), whose sum is σ = 1847577600. Its totient is φ = 184125504.

The previous prime is 645545513. The next prime is 645545567. The reversal of 645545544 is 445545546.

645545544 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 645545496 and 645545505.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 105727 + ... + 111665.

It is an arithmetic number, because the mean of its divisors is an integer number (28868400).

Almost surely, 2^645545544 is an apocalyptic number.

It is an amenable number.

645545544 is an abundant number, since it is smaller than the sum of its proper divisors (1202032056).

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

645545544 is a wasteful number, since it uses less digits than its factorization.

645545544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6602 (or 6598 counting only the distinct ones).

The product of its digits is 960000, while the sum is 42.

The square root of 645545544 is about 25407.5883153045. The cubic root of 645545544 is about 864.2557863214.

The spelling of 645545544 in words is "six hundred forty-five million, five hundred forty-five thousand, five hundred forty-four".