645588 has 36 divisors (see below), whose sum is σ = 1659840. Its totient is φ = 211536.

The previous prime is 645583. The next prime is 645599. The reversal of 645588 is 885546.

It is a happy number.

645588 is a `hidden beast` number, since 645 + 5 + 8 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nialpdrome in base 15.

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 645588.

It is not an unprimeable number, because it can be changed into a prime (645581) 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 11 ways as a sum of consecutive naturals, for example, 2731 + ... + 2957.

2⁶⁴⁵⁵⁸⁸ 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 645588, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (829920).

645588 is an abundant number, since it is smaller than the sum of its proper divisors (1014252).

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

645588 is a wasteful number, since it uses less digits than its factorization.

645588 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316 (or 311 counting only the distinct ones).

The product of its digits is 38400, while the sum is 36.

The square root of 645588 is about 803.4849096281. The cubic root of 645588 is about 86.4274732591.

The spelling of 645588 in words is "six hundred forty-five thousand, five hundred eighty-eight".