645065 has 8 divisors (see below), whose sum is σ = 819720. Its totient is φ = 485632.

The previous prime is 645049. The next prime is 645067. The reversal of 645065 is 560546.

It can be written as a sum of positive squares in 4 ways, for example, as 11449 + 633616 = 107^2 + 796^2 .

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 645065 - 2⁴ = 645049 is a prime.

It is a super-2 number, since 2×645065² = 832217708450, which contains 22 as substring.

It is an Ulam number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (645067) 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, 3710 + ... + 3879.

It is an arithmetic number, because the mean of its divisors is an integer number (102465).

2⁶⁴⁵⁰⁶⁵ is an apocalyptic number.

It is an amenable number.

645065 is a deficient number, since it is larger than the sum of its proper divisors (174655).

645065 is a wasteful number, since it uses less digits than its factorization.

645065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7611.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 645065 is about 803.1593864234. The cubic root of 645065 is about 86.4041282464.

The spelling of 645065 in words is "six hundred forty-five thousand, sixty-five".