645617 has 8 divisors (see below), whose sum is σ = 744000. Its totient is φ = 548784.

The previous prime is 645611. The next prime is 645629. The reversal of 645617 is 716546.

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 645617 - 2¹⁰ = 644593 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 645617.

It is not an unprimeable number, because it can be changed into a prime (645611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 734 + ... + 1352.

It is an arithmetic number, because the mean of its divisors is an integer number (93000).

2⁶⁴⁵⁶¹⁷ is an apocalyptic number.

It is an amenable number.

645617 is a deficient number, since it is larger than the sum of its proper divisors (98383).

645617 is a wasteful number, since it uses less digits than its factorization.

645617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 775.

The product of its digits is 5040, while the sum is 29.

The square root of 645617 is about 803.5029558129. The cubic root of 645617 is about 86.4287673554.

The spelling of 645617 in words is "six hundred forty-five thousand, six hundred seventeen".