641681785 has 8 divisors (see below), whose sum is σ = 777642696. Its totient is φ = 508262400.

The previous prime is 641681783. The next prime is 641681837. The reversal of 641681785 is 587186146.

It can be written as a sum of positive squares in 4 ways, for example, as 385297641 + 256384144 = 19629^2 + 16012^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 641681785 - 2¹ = 641681783 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641681783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 634824 + ... + 635833.

It is an arithmetic number, because the mean of its divisors is an integer number (97205337).

Almost surely, 2^641681785 is an apocalyptic number.

It is an amenable number.

641681785 is a deficient number, since it is larger than the sum of its proper divisors (135960911).

641681785 is a wasteful number, since it uses less digits than its factorization.

641681785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1270763.

The product of its digits is 322560, while the sum is 46.

The square root of 641681785 is about 25331.4386681846. The cubic root of 641681785 is about 862.5280690998.

The spelling of 641681785 in words is "six hundred forty-one million, six hundred eighty-one thousand, seven hundred eighty-five".