645017 has 4 divisors (see below), whose sum is σ = 665856. Its totient is φ = 624180.

The previous prime is 645013. The next prime is 645019. The reversal of 645017 is 710546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645017 - 2² = 645013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644983 and 645001.

It is not an unprimeable number, because it can be changed into a prime (645011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10373 + ... + 10434.

It is an arithmetic number, because the mean of its divisors is an integer number (166464).

2⁶⁴⁵⁰¹⁷ is an apocalyptic number.

It is an amenable number.

645017 is a deficient number, since it is larger than the sum of its proper divisors (20839).

645017 is a wasteful number, since it uses less digits than its factorization.

645017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20838.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 645017 is about 803.1295038784. The cubic root of 645017 is about 86.4019850510.

The spelling of 645017 in words is "six hundred forty-five thousand, seventeen".