645420243 has 16 divisors (see below), whose sum is σ = 928261376. Its totient is φ = 396537120.

The previous prime is 645420233. The next prime is 645420277. The reversal of 645420243 is 342024546.

645420243 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645420243 - 2⁵ = 645420211 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645420243.

It is not an unprimeable number, because it can be changed into a prime (645420233) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11496 + ... + 37722.

It is an arithmetic number, because the mean of its divisors is an integer number (58016336).

Almost surely, 2^645420243 is an apocalyptic number.

645420243 is a deficient number, since it is larger than the sum of its proper divisors (282841133).

645420243 is a wasteful number, since it uses less digits than its factorization.

645420243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26874.

The product of its (nonzero) digits is 23040, while the sum is 30.

The square root of 645420243 is about 25405.1223771900. The cubic root of 645420243 is about 864.1998650816.

Adding to 645420243 its reverse (342024546), we get a palindrome (987444789).

The spelling of 645420243 in words is "six hundred forty-five million, four hundred twenty thousand, two hundred forty-three".