641780648 has 8 divisors (see below), whose sum is σ = 1203338730. Its totient is φ = 320890320.

The previous prime is 641780641. The next prime is 641780683. The reversal of 641780648 is 846087146.

It can be written as a sum of positive squares in only one way, i.e., 524318404 + 117462244 = 22898^2 + 10838^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 641780599 and 641780608.

It is not an unprimeable number, because it can be changed into a prime (641780641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40111283 + ... + 40111298.

Almost surely, 2^641780648 is an apocalyptic number.

It is an amenable number.

641780648 is a deficient number, since it is larger than the sum of its proper divisors (561558082).

641780648 is a wasteful number, since it uses less digits than its factorization.

641780648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80222587 (or 80222583 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 44.

The square root of 641780648 is about 25333.3899823928. The cubic root of 641780648 is about 862.5723629828.

The spelling of 641780648 in words is "six hundred forty-one million, seven hundred eighty thousand, six hundred forty-eight".