646224020 has 24 divisors (see below), whose sum is σ = 1461461064. Its totient is φ = 238605696.

The previous prime is 646224013. The next prime is 646224079. The reversal of 646224020 is 20422646.

It can be written as a sum of positive squares in 4 ways, for example, as 108076816 + 538147204 = 10396^2 + 23198^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1242479 + ... + 1242998.

It is an arithmetic number, because the mean of its divisors is an integer number (60894211).

Almost surely, 2^646224020 is an apocalyptic number.

It is an amenable number.

646224020 is an abundant number, since it is smaller than the sum of its proper divisors (815237044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646224020 is a wasteful number, since it uses less digits than its factorization.

646224020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2485499 (or 2485497 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 26.

The square root of 646224020 is about 25420.9366467878. The cubic root of 646224020 is about 864.5584613248.

Adding to 646224020 its reverse (20422646), we get a palindrome (666646666).

The spelling of 646224020 in words is "six hundred forty-six million, two hundred twenty-four thousand, twenty".