641617709 has 8 divisors (see below), whose sum is σ = 651645720. Its totient is φ = 631665216.

The previous prime is 641617667. The next prime is 641617759. The reversal of 641617709 is 907716146.

It can be written as a sum of positive squares in 4 ways, for example, as 39062500 + 602555209 = 6250^2 + 24547^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 641617709 - 2¹⁶ = 641552173 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641617759) 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, 1634 + ... + 35859.

It is an arithmetic number, because the mean of its divisors is an integer number (81455715).

Almost surely, 2^641617709 is an apocalyptic number.

It is an amenable number.

641617709 is a deficient number, since it is larger than the sum of its proper divisors (10028011).

641617709 is a wasteful number, since it uses less digits than its factorization.

641617709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37759.

The product of its (nonzero) digits is 63504, while the sum is 41.

The square root of 641617709 is about 25330.1738841248. The cubic root of 641617709 is about 862.4993585096.

The spelling of 641617709 in words is "six hundred forty-one million, six hundred seventeen thousand, seven hundred nine".