645223210 has 8 divisors (see below), whose sum is σ = 1161401796. Its totient is φ = 258089280.

The previous prime is 645223207. The next prime is 645223217. The reversal of 645223210 is 12322546.

645223210 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 618566641 + 26656569 = 24871^2 + 5163^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (645223217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32261151 + ... + 32261170.

Almost surely, 2^645223210 is an apocalyptic number.

645223210 is a deficient number, since it is larger than the sum of its proper divisors (516178586).

645223210 is a wasteful number, since it uses less digits than its factorization.

645223210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64522328.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 645223210 is about 25401.2442608625. The cubic root of 645223210 is about 864.1119155510. Note that the first 3 decimals are identical.

Adding to 645223210 its reverse (12322546), we get a palindrome (657545756).

The spelling of 645223210 in words is "six hundred forty-five million, two hundred twenty-three thousand, two hundred ten".