641247640 has 32 divisors (see below), whose sum is σ = 1573972560. Its totient is φ = 233180800.

The previous prime is 641247619. The next prime is 641247641. The reversal of 641247640 is 46742146.

It is a super-2 number, since 2×641247640² = 822397071611139200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 641247596 and 641247605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641247641) 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 7 ways as a sum of consecutive naturals, for example, 728251 + ... + 729130.

Almost surely, 2^641247640 is an apocalyptic number.

It is an amenable number.

641247640 is an abundant number, since it is smaller than the sum of its proper divisors (932724920).

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

641247640 is a wasteful number, since it uses less digits than its factorization.

641247640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1457403 (or 1457399 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 34.

The square root of 641247640 is about 25322.8679260466. The cubic root of 641247640 is about 862.3335039537. Note that the first 3 decimals are identical.

Adding to 641247640 its reverse (46742146), we get a palindrome (687989786).

The spelling of 641247640 in words is "six hundred forty-one million, two hundred forty-seven thousand, six hundred forty".