645546 has 16 divisors (see below), whose sum is σ = 1408608. Its totient is φ = 195600.

The previous prime is 645529. The next prime is 645571.

645546 is nontrivially palindromic in base 10.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 4825 + ... + 4956.

It is an arithmetic number, because the mean of its divisors is an integer number (88038).

2⁶⁴⁵⁵⁴⁶ is an apocalyptic number.

645546 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

645546 is an abundant number, since it is smaller than the sum of its proper divisors (763062).

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

645546 is a wasteful number, since it uses less digits than its factorization.

645546 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9797.

The product of its digits is 14400, while the sum is 30.

The square root of 645546 is about 803.4587730556. The cubic root of 645546 is about 86.4255989819.

The spelling of 645546 in words is "six hundred forty-five thousand, five hundred forty-six".