645576 has 32 divisors (see below), whose sum is σ = 1659840. Its totient is φ = 209088.

The previous prime is 645571. The next prime is 645577. The reversal of 645576 is 675546.

645576 = T₁₆₈ + T₁₆₉ + ... + T₂₀₄.

645576 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (645571) 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, 525 + ... + 1251.

It is an arithmetic number, because the mean of its divisors is an integer number (51870).

2⁶⁴⁵⁵⁷⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645576, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (829920).

645576 is an abundant number, since it is smaller than the sum of its proper divisors (1014264).

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

645576 is a wasteful number, since it uses less digits than its factorization.

645576 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 773 (or 769 counting only the distinct ones).

The product of its digits is 25200, while the sum is 33.

The square root of 645576 is about 803.4774421227. The cubic root of 645576 is about 86.4269377596.

It can be divided in two parts, 645 and 576, that added together give a palindrome (1221).

The spelling of 645576 in words is "six hundred forty-five thousand, five hundred seventy-six".