645865845 has 8 divisors (see below), whose sum is σ = 1033385376. Its totient is φ = 344461776.

The previous prime is 645865789. The next prime is 645865859. The reversal of 645865845 is 548568546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 645865845 - 2¹¹ = 645863797 is a prime.

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, 21528847 + ... + 21528876.

It is an arithmetic number, because the mean of its divisors is an integer number (129173172).

Almost surely, 2^645865845 is an apocalyptic number.

It is an amenable number.

645865845 is a deficient number, since it is larger than the sum of its proper divisors (387519531).

645865845 is a wasteful number, since it uses less digits than its factorization.

645865845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43057731.

The product of its digits is 4608000, while the sum is 51.

The square root of 645865845 is about 25413.8907883071. The cubic root of 645865845 is about 864.3987022495.

The spelling of 645865845 in words is "six hundred forty-five million, eight hundred sixty-five thousand, eight hundred forty-five".