641444240 has 80 divisors (see below), whose sum is σ = 1561507200. Its totient is φ = 245049728.

The previous prime is 641444197. The next prime is 641444249. The reversal of 641444240 is 42444146.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×641444240² = 822901426058355200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (641444249) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 973031 + ... + 973689.

It is an arithmetic number, because the mean of its divisors is an integer number (19518840).

Almost surely, 2^641444240 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 641444240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (780753600).

641444240 is an abundant number, since it is smaller than the sum of its proper divisors (920062960).

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

641444240 is an equidigital number, since it uses as much as digits as its factorization.

641444240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741 (or 689 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 29.

The square root of 641444240 is about 25326.7494953458. The cubic root of 641444240 is about 862.4216225075.

Adding to 641444240 its reverse (42444146), we get a palindrome (683888386).

The spelling of 641444240 in words is "six hundred forty-one million, four hundred forty-four thousand, two hundred forty".