645345253 has 8 divisors (see below), whose sum is σ = 737694080. Its totient is φ = 553035600.

The previous prime is 645345251. The next prime is 645345263. The reversal of 645345253 is 352543546.

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

It is a cyclic number.

It is not a de Polignac number, because 645345253 - 2¹ = 645345251 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645345251) 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 7 ways as a sum of consecutive naturals, for example, 49303 + ... + 61003.

It is an arithmetic number, because the mean of its divisors is an integer number (92211760).

Almost surely, 2^645345253 is an apocalyptic number.

It is an amenable number.

645345253 is a deficient number, since it is larger than the sum of its proper divisors (92348827).

645345253 is a wasteful number, since it uses less digits than its factorization.

645345253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19587.

The product of its digits is 216000, while the sum is 37.

The square root of 645345253 is about 25403.6464508543. The cubic root of 645345253 is about 864.1663939395.

Adding to 645345253 its reverse (352543546), we get a palindrome (997888799).

The spelling of 645345253 in words is "six hundred forty-five million, three hundred forty-five thousand, two hundred fifty-three".