645356842 has 16 divisors (see below), whose sum is σ = 1045801512. Its totient is φ = 296913600.

The previous prime is 645356827. The next prime is 645356861. The reversal of 645356842 is 248653546.

It can be written as a sum of positive squares in 4 ways, for example, as 133194681 + 512162161 = 11541^2 + 22631^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30909 + ... + 47392.

Almost surely, 2^645356842 is an apocalyptic number.

645356842 is a deficient number, since it is larger than the sum of its proper divisors (400444670).

645356842 is a wasteful number, since it uses less digits than its factorization.

645356842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78633.

The product of its digits is 691200, while the sum is 43.

The square root of 645356842 is about 25403.8745470056. The cubic root of 645356842 is about 864.1715667595.

The spelling of 645356842 in words is "six hundred forty-five million, three hundred fifty-six thousand, eight hundred forty-two".