645766 has 16 divisors (see below), whose sum is σ = 1069200. Its totient is φ = 290080.

The previous prime is 645763. The next prime is 645787. The reversal of 645766 is 667546.

645766 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645763) 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, 3180 + ... + 3376.

It is an arithmetic number, because the mean of its divisors is an integer number (66825).

2⁶⁴⁵⁷⁶⁶ is an apocalyptic number.

645766 is a deficient number, since it is larger than the sum of its proper divisors (423434).

645766 is a wasteful number, since it uses less digits than its factorization.

645766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359.

The product of its digits is 30240, while the sum is 34.

The square root of 645766 is about 803.5956694756. The cubic root of 645766 is about 86.4354157222.

The spelling of 645766 in words is "six hundred forty-five thousand, seven hundred sixty-six".