645211 has 4 divisors (see below), whose sum is σ = 737392. Its totient is φ = 553032.

The previous prime is 645187. The next prime is 645233. The reversal of 645211 is 112546.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645211 - 2⁵ = 645179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645011) 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 3 ways as a sum of consecutive naturals, for example, 46080 + ... + 46093.

It is an arithmetic number, because the mean of its divisors is an integer number (184348).

2⁶⁴⁵²¹¹ is an apocalyptic number.

645211 is a deficient number, since it is larger than the sum of its proper divisors (92181).

645211 is an equidigital number, since it uses as much as digits as its factorization.

645211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92180.

The product of its digits is 240, while the sum is 19.

The square root of 645211 is about 803.2502723311. The cubic root of 645211 is about 86.4106464790.

Adding to 645211 its reverse (112546), we get a palindrome (757757).

The spelling of 645211 in words is "six hundred forty-five thousand, two hundred eleven".