645505 has 8 divisors (see below), whose sum is σ = 885312. Its totient is φ = 442608.

The previous prime is 645503. The next prime is 645521. The reversal of 645505 is 505546.

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 645505 - 2¹ = 645503 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 645505.

It is not an unprimeable number, because it can be changed into a prime (645503) 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, 9187 + ... + 9256.

It is an arithmetic number, because the mean of its divisors is an integer number (110664).

2⁶⁴⁵⁵⁰⁵ is an apocalyptic number.

It is an amenable number.

645505 is a deficient number, since it is larger than the sum of its proper divisors (239807).

645505 is a wasteful number, since it uses less digits than its factorization.

645505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18455.

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 645505 is about 803.4332579624. The cubic root of 645505 is about 86.4237692519.

The spelling of 645505 in words is "six hundred forty-five thousand, five hundred five".