641431759621 has 4 divisors (see below), whose sum is σ = 641561793292. Its totient is φ = 641301725952.

The previous prime is 641431759603. The next prime is 641431759637. The reversal of 641431759621 is 126957134146.

641431759621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 126957134146 = 2 ⋅63478567073.

It can be written as a sum of positive squares in 2 ways, for example, as 233251327521 + 408180432100 = 482961^2 + 638890^2 .

It is a cyclic number.

It is not a de Polignac number, because 641431759621 - 2¹¹ = 641431757573 is a prime.

It is a super-2 number, since 2×641431759621² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641431759021) 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, 65009436 + ... + 65019301.

It is an arithmetic number, because the mean of its divisors is an integer number (160390448323).

Almost surely, 2^641431759621 is an apocalyptic number.

It is an amenable number.

641431759621 is a deficient number, since it is larger than the sum of its proper divisors (130033671).

641431759621 is a wasteful number, since it uses less digits than its factorization.

641431759621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130033670.

The product of its digits is 1088640, while the sum is 49.

The spelling of 641431759621 in words is "six hundred forty-one billion, four hundred thirty-one million, seven hundred fifty-nine thousand, six hundred twenty-one".