641218857197 has 4 divisors (see below), whose sum is σ = 641228498460. Its totient is φ = 641209215936.

The previous prime is 641218857173. The next prime is 641218857239. The reversal of 641218857197 is 791758812146.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 791758812146 = 2 ⋅395879406073.

It can be written as a sum of positive squares in 2 ways, for example, as 303348694441 + 337870162756 = 550771^2 + 581266^2 .

It is a cyclic number.

It is not a de Polignac number, because 641218857197 - 2¹⁴ = 641218840813 is a prime.

It is a super-3 number, since 3×641218857197³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641218857127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4720172 + ... + 4854117.

It is an arithmetic number, because the mean of its divisors is an integer number (160307124615).

Almost surely, 2^641218857197 is an apocalyptic number.

It is an amenable number.

641218857197 is a deficient number, since it is larger than the sum of its proper divisors (9641263).

641218857197 is an equidigital number, since it uses as much as digits as its factorization.

641218857197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9641262.

The product of its digits is 6773760, while the sum is 59.

The spelling of 641218857197 in words is "six hundred forty-one billion, two hundred eighteen million, eight hundred fifty-seven thousand, one hundred ninety-seven".