641727440 has 20 divisors (see below), whose sum is σ = 1492016484. Its totient is φ = 256690944.

The previous prime is 641727421. The next prime is 641727461. The reversal of 641727440 is 44727146.

It can be written as a sum of positive squares in 2 ways, for example, as 506610064 + 135117376 = 22508^2 + 11624^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 641727440.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4010717 + ... + 4010876.

Almost surely, 2^641727440 is an apocalyptic number.

It is an amenable number.

641727440 is an abundant number, since it is smaller than the sum of its proper divisors (850289044).

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

641727440 is a wasteful number, since it uses less digits than its factorization.

641727440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8021606 (or 8021600 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 35.

The square root of 641727440 is about 25332.3398050792. The cubic root of 641727440 is about 862.5485246101.

The spelling of 641727440 in words is "six hundred forty-one million, seven hundred twenty-seven thousand, four hundred forty".