645801 has 16 divisors (see below), whose sum is σ = 960960. Its totient is φ = 383040.

The previous prime is 645787. The next prime is 645803. The reversal of 645801 is 108546.

It is not a de Polignac number, because 645801 - 2⁶ = 645737 is a prime.

It is an Ulam number.

It is a Curzon number.

645801 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (645803) 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 15 ways as a sum of consecutive naturals, for example, 846 + ... + 1416.

It is an arithmetic number, because the mean of its divisors is an integer number (60060).

2⁶⁴⁵⁸⁰¹ is an apocalyptic number.

It is an amenable number.

645801 is a deficient number, since it is larger than the sum of its proper divisors (315159).

645801 is a wasteful number, since it uses less digits than its factorization.

645801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616.

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 645801 is about 803.6174463014. The cubic root of 645801 is about 86.4369772707.

The spelling of 645801 in words is "six hundred forty-five thousand, eight hundred one".