645541617 has 16 divisors (see below), whose sum is σ = 988682112. Its totient is φ = 367006080.

The previous prime is 645541607. The next prime is 645541619. The reversal of 645541617 is 716145546.

It is not a de Polignac number, because 645541617 - 2¹⁰ = 645540593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645541619) by changing a digit.

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, 73884 + ... + 82157.

It is an arithmetic number, because the mean of its divisors is an integer number (61792632).

Almost surely, 2^645541617 is an apocalyptic number.

It is an amenable number.

645541617 is a deficient number, since it is larger than the sum of its proper divisors (343140495).

645541617 is a wasteful number, since it uses less digits than its factorization.

645541617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156248.

The product of its digits is 100800, while the sum is 39.

The square root of 645541617 is about 25407.5110351250. The cubic root of 645541617 is about 864.2540338299.

The spelling of 645541617 in words is "six hundred forty-five million, five hundred forty-one thousand, six hundred seventeen".