645324217 has 4 divisors (see below), whose sum is σ = 645410176. Its totient is φ = 645238260.

The previous prime is 645324193. The next prime is 645324223. The reversal of 645324217 is 712423546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645324217 - 2²⁷ = 511106489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645324247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30513 + ... + 47134.

It is an arithmetic number, because the mean of its divisors is an integer number (161352544).

Almost surely, 2^645324217 is an apocalyptic number.

It is an amenable number.

645324217 is a deficient number, since it is larger than the sum of its proper divisors (85959).

645324217 is an equidigital number, since it uses as much as digits as its factorization.

645324217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85958.

The product of its digits is 40320, while the sum is 34.

The square root of 645324217 is about 25403.2324124313. The cubic root of 645324217 is about 864.1570042360.

The spelling of 645324217 in words is "six hundred forty-five million, three hundred twenty-four thousand, two hundred seventeen".