645858644 has 12 divisors (see below), whose sum is σ = 1130438484. Its totient is φ = 322876224.

The previous prime is 645858641. The next prime is 645858673. The reversal of 645858644 is 446858546.

645858644 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 153462544 + 492396100 = 12388^2 + 22190^2 .

It is a junction number, because it is equal to n+sod(n) for n = 645858592 and 645858601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645858641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29174 + ... + 46290.

It is an arithmetic number, because the mean of its divisors is an integer number (94203207).

Almost surely, 2^645858644 is an apocalyptic number.

It is an amenable number.

645858644 is a deficient number, since it is larger than the sum of its proper divisors (484579840).

645858644 is a wasteful number, since it uses less digits than its factorization.

645858644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26554 (or 26552 counting only the distinct ones).

The product of its digits is 3686400, while the sum is 50.

The square root of 645858644 is about 25413.7491134228. The cubic root of 645858644 is about 864.3954897360.

The spelling of 645858644 in words is "six hundred forty-five million, eight hundred fifty-eight thousand, six hundred forty-four".