645829 has 6 divisors (see below), whose sum is σ = 681990. Its totient is φ = 611496.

The previous prime is 645803. The next prime is 645833. The reversal of 645829 is 928546.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 636804 + 9025 = 798^2 + 95^2 .

It is not a de Polignac number, because 645829 - 2¹¹ = 643781 is a prime.

It is a Duffinian number.

645829 is a lucky number.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 645794 and 645803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645839) 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 5 ways as a sum of consecutive naturals, for example, 534 + ... + 1255.

It is an arithmetic number, because the mean of its divisors is an integer number (113665).

2⁶⁴⁵⁸²⁹ is an apocalyptic number.

It is an amenable number.

645829 is a deficient number, since it is larger than the sum of its proper divisors (36161).

645829 is a wasteful number, since it uses less digits than its factorization.

645829 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1827 (or 1808 counting only the distinct ones).

The product of its digits is 17280, while the sum is 34.

The square root of 645829 is about 803.6348673372. The cubic root of 645829 is about 86.4382264689.

The spelling of 645829 in words is "six hundred forty-five thousand, eight hundred twenty-nine".