641940640 has 48 divisors (see below), whose sum is σ = 1654460640. Its totient is φ = 233432320.

The previous prime is 641940623. The next prime is 641940641. The reversal of 641940640 is 46049146.

It is a junction number, because it is equal to n+sod(n) for n = 641940596 and 641940605.

It is not an unprimeable number, because it can be changed into a prime (641940641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180610 + ... + 184129.

It is an arithmetic number, because the mean of its divisors is an integer number (34467930).

Almost surely, 2^641940640 is an apocalyptic number.

It is an amenable number.

641940640 is an abundant number, since it is smaller than the sum of its proper divisors (1012520000).

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

641940640 is a wasteful number, since it uses less digits than its factorization.

641940640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364765 (or 364757 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 641940640 is about 25336.5475153976. The cubic root of 641940640 is about 862.6440350364.

Adding to 641940640 its reverse (46049146), we get a palindrome (687989786).

The spelling of 641940640 in words is "six hundred forty-one million, nine hundred forty thousand, six hundred forty".