645817 has 8 divisors (see below), whose sum is σ = 690624. Its totient is φ = 602448.

The previous prime is 645803. The next prime is 645833. The reversal of 645817 is 718546.

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 645817 - 2¹⁵ = 613049 is a prime.

It is a pancake number, because a pancake can be divided into 645817 parts by 1136 straight cuts.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645857) 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, 663 + ... + 1315.

It is an arithmetic number, because the mean of its divisors is an integer number (86328).

2⁶⁴⁵⁸¹⁷ is an apocalyptic number.

It is an amenable number.

645817 is a deficient number, since it is larger than the sum of its proper divisors (44807).

645817 is a wasteful number, since it uses less digits than its factorization.

645817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 719.

The product of its digits is 6720, while the sum is 31.

The square root of 645817 is about 803.6274012252. The cubic root of 645817 is about 86.4376911027.

The spelling of 645817 in words is "six hundred forty-five thousand, eight hundred seventeen".