645854 has 16 divisors (see below), whose sum is σ = 1092096. Its totient is φ = 283800.

The previous prime is 645851. The next prime is 645857. The reversal of 645854 is 458546.

It is an interprime number because it is at equal distance from previous prime (645851) and next prime (645857).

It is a self number, because there is not a number n which added to its sum of digits gives 645854.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645854.

It is not an unprimeable number, because it can be changed into a prime (645851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 209 + ... + 1155.

It is an arithmetic number, because the mean of its divisors is an integer number (68256).

2⁶⁴⁵⁸⁵⁴ is an apocalyptic number.

645854 is a deficient number, since it is larger than the sum of its proper divisors (446242).

645854 is a wasteful number, since it uses less digits than its factorization.

645854 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 991.

The product of its digits is 19200, while the sum is 32.

The square root of 645854 is about 803.6504215142. The cubic root of 645854 is about 86.4393417940.

The spelling of 645854 in words is "six hundred forty-five thousand, eight hundred fifty-four".