645707 has 4 divisors (see below), whose sum is σ = 652080. Its totient is φ = 639336.

The previous prime is 645703. The next prime is 645713. The reversal of 645707 is 707546.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645707 - 2² = 645703 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 645707.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645707.

It is not an unprimeable number, because it can be changed into a prime (645703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3032 + ... + 3237.

It is an arithmetic number, because the mean of its divisors is an integer number (163020).

2⁶⁴⁵⁷⁰⁷ is an apocalyptic number.

645707 is a deficient number, since it is larger than the sum of its proper divisors (6373).

645707 is a wasteful number, since it uses less digits than its factorization.

645707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6372.

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 645707 is about 803.5589586334. The cubic root of 645707 is about 86.4327832697.

The spelling of 645707 in words is "six hundred forty-five thousand, seven hundred seven".