645909545 has 8 divisors (see below), whose sum is σ = 775583424. Its totient is φ = 516399664.

The previous prime is 645909527. The next prime is 645909557. The reversal of 645909545 is 545909546.

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

It is a cyclic number.

It is not a de Polignac number, because 645909545 - 2²² = 641715241 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645909545.

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, 32159 + ... + 48228.

It is an arithmetic number, because the mean of its divisors is an integer number (96947928).

Almost surely, 2^645909545 is an apocalyptic number.

It is an amenable number.

645909545 is a deficient number, since it is larger than the sum of its proper divisors (129673879).

645909545 is a wasteful number, since it uses less digits than its factorization.

645909545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81999.

The product of its (nonzero) digits is 972000, while the sum is 47.

The square root of 645909545 is about 25414.7505397948. The cubic root of 645909545 is about 864.4181972017.

Subtracting from 645909545 its reverse (545909546), we obtain a palindrome (99999999).

The spelling of 645909545 in words is "six hundred forty-five million, nine hundred nine thousand, five hundred forty-five".