646205042 has 12 divisors (see below), whose sum is σ = 1127562030. Its totient is φ = 276944976.

The previous prime is 646205041. The next prime is 646205051. The reversal of 646205042 is 240502646.

It can be written as a sum of positive squares in only one way, i.e., 394379881 + 251825161 = 19859^2 + 15869^2 .

It is a junction number, because it is equal to n+sod(n) for n = 646204996 and 646205014.

It is not an unprimeable number, because it can be changed into a prime (646205041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3296867 + ... + 3297062.

Almost surely, 2^646205042 is an apocalyptic number.

646205042 is a deficient number, since it is larger than the sum of its proper divisors (481356988).

646205042 is a wasteful number, since it uses less digits than its factorization.

646205042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6593945 (or 6593938 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 29.

The square root of 646205042 is about 25420.5633690522. The cubic root of 646205042 is about 864.5499979279.

Adding to 646205042 its reverse (240502646), we get a palindrome (886707688).

The spelling of 646205042 in words is "six hundred forty-six million, two hundred five thousand, forty-two".