645006 has 16 divisors (see below), whose sum is σ = 1299024. Its totient is φ = 213504.

The previous prime is 644999. The next prime is 645011. The reversal of 645006 is 600546.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

645006 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 880 + ... + 1436.

It is an arithmetic number, because the mean of its divisors is an integer number (81189).

2⁶⁴⁵⁰⁰⁶ is an apocalyptic number.

645006 is an abundant number, since it is smaller than the sum of its proper divisors (654018).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645006 is a wasteful number, since it uses less digits than its factorization.

645006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 755.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 645006 is about 803.1226556386. The cubic root of 645006 is about 86.4014938871.

The spelling of 645006 in words is "six hundred forty-five thousand, six".