646621648 has 20 divisors (see below), whose sum is σ = 1253364100. Its totient is φ = 323172864.

The previous prime is 646621627. The next prime is 646621669. The reversal of 646621648 is 846126646.

It is an interprime number because it is at equal distance from previous prime (646621627) and next prime (646621669).

It can be written as a sum of positive squares in 2 ways, for example, as 580231744 + 66389904 = 24088^2 + 8148^2 .

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 37528 + ... + 51976.

It is an arithmetic number, because the mean of its divisors is an integer number (62668205).

Almost surely, 2^646621648 is an apocalyptic number.

It is an amenable number.

646621648 is a deficient number, since it is larger than the sum of its proper divisors (606742452).

646621648 is a wasteful number, since it uses less digits than its factorization.

646621648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17254 (or 17248 counting only the distinct ones).

The product of its digits is 331776, while the sum is 43.

The square root of 646621648 is about 25428.7563203551. The cubic root of 646621648 is about 864.7357487444.

The spelling of 646621648 in words is "six hundred forty-six million, six hundred twenty-one thousand, six hundred forty-eight".